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Indexes or Indices – The Plural Debate

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Indexes or Indices – The Plural Debate

| Candace Osmond

| Usage

| Candace Osmond

| Usage

Candace Osmond

Candace Osmond studied Advanced Writing & Editing Essentials at MHC. She’s been an International and USA TODAY Bestselling Author for over a decade. And she’s worked as an Editor for several mid-sized publications. Candace has a keen eye for content editing and a high degree of expertise in Fiction.

Some words and terms have more than one plural form, such as “index.” The noun that means an “indicator” or “a list of specific datum” has two acceptable plurals: “indexes” and “indices.”

Want to know a little secret regarding indexes vs. indices? Keep reading to learn when to use the two words and which word is better for the UK and American writing.

What is the Plural of Index?

Both “indexes” and “indices” are correct English plurals of the singular noun “index.” But there is a preference for indices outside North America because of solid adherence to Latin plurals.

Indexes or Indices?

Plurals of nouns take different rules. Some only need an -s or -es at the end, while others require a change in spelling. A few nouns like “index” follow both rules.

The word “index” is a noun that means:

An alphabetically-arranged list of some specific datum, like subject, keyword, or author.

A number from several observations that serve as a measure or indicator.

A device that shows quantity or value.

“Index” can also be a verb that means to record specific information in a list.

In the battle of indexes versus indices, the frequency of indexes is much lower than indices. This Google Ngram Viewer shows that many writers prefer indices over indexes.

When to Use Indexes

The main difference between indices and indexes is that indexes is the Anglicization of indices. It’s wise to use “indexes” in your writing as a non-technical plural form or in an informal context. But some books that cater to formal writing settings still prefer “indexes.”

Language experts also agree that you should use “indexes” when referring to citation listings, bibliographies, and other written documents.

You should also use indexes over indices if you’re following the AP style guide.

American English Indexes vs. Indices usage trend.

The use of “indexes” also depends on the English variation. American usage and style and Canadian style guides prefer the regular plural version of “index.”

Bryan Garner wrote about the issue of indexes and indices, saying that the latter sounds pretentious. Therefore, “indexes” is always your safest choice.

The verb indexes can also be defined as the singular form, third person, present tense of “index.”

When to Use Indices

“Indices” is the irregular plural form of “index.” Irregular or foreign plurals are formed based on the language rule where they originate. For instance, “indices” has Latin roots.

Technical contexts prefer indices to indexes. The S&P Dow Jones Indices, the leading resource for investable indices, follows this form.

While “indexes” is more suitable for popular writing, the technical use of “indices” fits more in statistical contexts. You’ll rarely see non-technical writings saying “book indices” at the back.

Merriam-Webster shows evidence that “indices” is standard in the mathematical context. It explicitly defines “indices” as numbers, expressions, or symbols connected with another to show a mathematical operation.

British English Indexes vs. Indices usage trend.

There is also an advantage for indices in the UK and other areas outside North America.

Indexes in a Sentence

Stock indexes staged a comeback Thursday afternoon as investors digested minutes from the March Federal Open Market Committee meeting, released Wednesday, showing the central bank weighing a plan to reduce its bond holdings by $95 billion per month as it tries to stamp out surging inflation. (Market Watch)

S&P Dow Jones Indices also said it was consulting with market participants on potentially removing Russian bonds from its fixed-income indexes. FTSE Russell made a similar move last week. (Wall Street Journal)

Minutes to the latest Federal Open Market Committee (FOMC) from mid-last month came out earlier this afternoon, and markets took that opportunity to drop lower across all major indexes. (Nasdaq)

Indices in a Sentence

Equity benchmark indices opened in red on Tuesday with Sensex down by 294.10 points and Nifty by 100.80 points. (The Print)

Oil majors and banks keep blue-chip index in positive territory as global indices slide. (Financial Times)

The FTSE 100 gained over 1% last week as most US, Asian and European equity indices ended the week in negative territory, weighed down by a firm hawkish outlook from the US Federal Reserve (Fed) and worries about the outcome of the first round of presidential elections in France. (IG)

Index Synonyms

Indicator.

Ratio.

Clue.

Basis.

Formula.

Guide.

Needle.

Pointer.

Model.

Indication.

Mark.

Indicia.

Symbol.

Indexes vs. Indices Summary

Which word wins in the battle of indexes vs. indices? The truth is that both words are standard plurals of the noun index. But here’s a better way to use them:

Use indexes for informal writing, AP style rule adherence, and modern American usage.

Use indices for technical and formal contexts and if your audience is from the UK or other countries outside North America.

Have a gander around our site for more helpful guides like this to improve your writing skills! Like this one on the usage of the idiom easy pickings.

Grammarist is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. When you buy via the links on our site, we may earn an affiliate commission at no cost to you.

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What Is an Index? Examples, How It's Used, and How to Invest

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What Is an Index?

Understanding Indexes

Index Investing

Examples

FAQs

The Bottom Line

Fund Trading

Index Trading Strategy

What Is an Index? Examples, How It's Used, and How to Invest

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What Is an Index?

A financial index produces a numeric score based on inputs such as a variety of asset prices. It can be used to track the performance of a group of assets in a standardized way. Indexes typically measure the performance of a basket of securities intended to replicate a certain area of the market.

These could be constructed as a broad-based index that captures the entire market, such as the Standard & Poor's 500 Index or Dow Jones Industrial Average (DJIA), or more specialized such as indexes that track a particular industry or segment such as the Russell 2000 Index, which tracks only small-cap stocks.

Key Takeaways

An index measures the price performance of a basket of securities using a standardized metric and methodology.Indexes in financial markets are often used as benchmarks to evaluate an investment's performance against.Some of the most important indexes in the U.S. markets are the S&P 500 and the Dow Jones Industrial Average.Passive index investing has become a popular low-cost way to replicate the returns of popular indices such as the S&P 500 Index or Dow Jones Industrial Average.Benchmarking your investment strategy against the appropriate index is key to understanding a portfolio's performance.

Investopedia / Mira Norian

Understanding Indexes

Indexes are also created to measure other financial or economic data such as interest rates, inflation, or manufacturing output. Indexes often serve as benchmarks against which to evaluate the performance of a portfolio's returns. One popular investment strategy, known as indexing, is to try to replicate such an index in a passive manner rather than trying to outperform it.

Indexes in finance are typically used to track a statistical measure of change in various security prices. In finance, it typically refers to a statistical measure of change in a securities market. In the case of financial markets, stock and bond market indexes consist of a hypothetical portfolio of securities representing a particular market or a segment of it. (You cannot invest directly in an index.) The S&P 500 Index and the Bloomberg US Aggregate Bond Index are common benchmarks for the U.S. stock and bond markets, respectively. In reference to mortgages, it refers to a benchmark interest rate created by a third party.

Each index related to the stock and bond markets has its own calculation methodology. In most cases, the relative change of an index is more important than the actual numeric value representing the index. For example, if the FTSE 100 Index is at 6,670.40, that number tells investors the index is nearly seven times its base level of 1,000. However, to assess how the index has changed from the previous day, investors must look at the amount the index has fallen, often expressed as a percentage.

Index Investing

Indexes are also often used as benchmarks against which to measure the performance of mutual funds and exchange-traded funds (ETFs). For instance, many mutual funds compare their returns to the return in the S&P 500 Index to give investors a sense of how much more or less the managers are earning on their money than they would make in an index fund.

"Indexing" is a form of passive fund management. Instead of a fund portfolio manager actively stock picking and market timing—that is, choosing securities to invest in and strategizing when to buy and sell them—the fund manager builds a portfolio wherein the holdings mirror the securities of a particular index. The idea is that by mimicking the profile of the index—the stock market as a whole, or a broad segment of it—the fund will match its performance as well.

Since you cannot invest directly in an index, index funds are created to track their performance. These funds incorporate securities that closely mimic those found in an index, thereby allowing an investor to bet on its performance, for a fee. An example of a popular index fund is the Vanguard S&P 500 ETF (VOO), which closely mirrors the S&P 500 Index.

When putting together mutual funds and ETFs, fund sponsors attempt to create portfolios mirroring the components of a certain index. This allows an investor to buy a security likely to rise and fall in tandem with the stock market as a whole or with a segment of the market.

Index Examples

The S&P 500 Index is one of the world's best-known indexes and one of the most commonly used benchmarks for the stock market. It includes 80% of the total stocks traded in the United States. Conversely, the Dow Jones Industrial Average is also well known, but represents stock values from just 30 of the nation's publicly traded companies. Other prominent indexes include the Nasdaq 100 Index, Wilshire 5000 Total Market Index, MSCI EAFE Index, and the Bloomberg US Aggregate Bond Index.

Like mutual funds, indexed annuities are tied to a trading index. However, rather than the fund sponsor trying to put together an investment portfolio likely to closely mimic the index in question, these securities feature a rate of return that follows a particular index but typically have caps on the returns they provide. For example, if an investor buys an annuity indexed to the Dow Jones and it has a cap of 10%, its rate of return will be between 0 and 10%, depending on the annual changes to that index. Indexed annuities allow investors to buy securities that grow along with broad market segments or the total market.

Adjustable-rate mortgages feature interest rates that adjust over the life of the loan. The adjustable interest rate is determined by adding a margin to an index. One of the most popular indexes on which mortgages are based is the London Inter-bank Offer Rate (LIBOR). For example, if a mortgage indexed to the LIBOR has a 2% margin and the LIBOR is 3%, the interest rate on the loan is 5%.

What Is an Index Fund?

An index fund is a mutual fund or ETF that seeks to replicate the performance of an index, often by constructing its portfolio to mirror that of the index itself. Index investing is considered a passive strategy since it does not involve any stock picking or active management. Studies show that over time, indexing strategies tend to perform better than stock picking strategies. Because they are passive index funds also tend to have lower fees and tax exposure.

What Are Different Ways to Construct an Index?

Indexes can be built in a number of ways, often with consideration to how to weight the various components of the index. The three main ways include:A market-cap, or capitalization-weighted index puts more weight in the index to those components that have the largest market capitalization (market value), such as the S&P 500A price-weighted index puts more weight to those components with the highest prices (such as the Dow Jones Industrial Average)An equal-weighted index allocates each component with the same weights (this is sometimes called an unweighted index)

Why Are Indexes Useful?

Indexes are useful for providing valid benchmarks against which to measure investment performance for a given strategy or portfolio. By understanding how a strategy does relative to a benchmark, one can understand its true performance.Indexes also provide investors with a simplified snapshot of a large market sector, without having to examine every single asset in that index. For example, it would be impractical for an ordinary investor to study hundreds of different stock prices in order to understand the changing fortunes of different technology companies. A sector-specific index can show the average trend for the sector.

What Are Some Major Stock Indexes?

In the United States, the three leading stock indexes are the Dow Jones Industrial Average, the S&P 500, the Nasdaq Composite, and the Russell 2000. For international markets, the Financial Times Stock Exchange 100 (FTSE 100) Index and the Nikkei 225 Index are popular proxies for the British and Japanese stock markets, respectively. Most countries with stock exchanges publish at least one index for their major stocks.

What Are Some Bond Indexes?

While stock market indexes may most often come to mind, indexes are also constructed around other asset classes. In the bond market, for example, the Bloomberg Aggregate Bond Index tracks the investment grade bond market, while the Emerging Market Bond Index looks at government bonds of emerging market economies.

The Bottom Line

Market indexes provide a broad representation of how markets are performing. These indexes serve as benchmarks to gauge the movement and performance of market segments. Investors also use indexes as a basis for portfolio or passive index investing. In the U.S. such representative indexes include the large-cap S&P 500 and the technology-heavy Nasdaq 100.

Article Sources

Investopedia requires writers to use primary sources to support their work. These include white papers, government data, original reporting, and interviews with industry experts. We also reference original research from other reputable publishers where appropriate. You can learn more about the standards we follow in producing accurate, unbiased content in our

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S&P Dow Jones Indices. "S&P 500."

Bloomberg Barclays Indices. "US Aggregate Index," Page 1.

FTSE Russell. "FTSE 100 Index," Pages 1-2.

Vanguard. "Vanguard S&P 500 ETF (VOO)."

S&P Dow Jones Indices. "Dow Jones Industrial Average."

Nasdaq. "NASDAQ 100," Page 1.

Wilshire. "Wilshire 5000 Total Market Index."

MSCI. "MSCI EAFE Index," Page 1.

S&P Dow Jones Indices. “SPIVA Report Card.”

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Part Of

Guide to Index Fund Investing

What Are Index Funds, and How Do They Work?

1 of 19

What Is an Index? Examples, How It's Used, and How to Invest

2 of 19

Investing in Index Funds: What You Need to Know

3 of 19

Is it Possible to Invest in an Index?

4 of 19

The Lowdown on Index Funds

5 of 19

Tracker Fund: What it is, How it Works, Examples

6 of 19

How to Invest in the S&P 500

7 of 19

Top S&P 500 Index Funds

8 of 19

Put $10,000 in the S&P 500 ETF and Wait 20 Years

9 of 19

How Vanguard Index Funds Work

10 of 19

Vanguard Total Stock Market Index Fund vs. Vanguard 500 Index Fund: What’s the Difference?

11 of 19

The 4 Best Total Market Index Funds

12 of 19

Five Good Small Cap U.S. Index Funds

13 of 19

Index Mutual Funds Vs. Index ETFs

14 of 19

5 Potential Warnings About Index Funds

15 of 19

5 Reasons to Avoid Index Funds

16 of 19

Can an Index Fund Investor Lose Everything?

17 of 19

What Is a Good Expense Ratio for Mutual Funds?

18 of 19

The Hidden Differences Among Index Funds

19 of 19

Related Terms

Market Index: Definition, How Indexing Works, Types, and Examples

A market index is a hypothetical portfolio representing a segment of the financial market. Popular indexes include the Dow Jones, S&P 500, and Nasdaq.

Indexing: Definition and Uses in Economics and Investing

Indexing may be a statistical measure for tracking economic data, a methodology for grouping a specific market segment, or an investment management strategy for passive investments.

Passive ETF: What It Means, How It Works

A passive ETF is a method of investing in an entire index or sector with the benefits of low costs and transparency that are absent in active investing.

MSCI All Country World Index (ACWI): Definition and Countries

The MSCI All Country World Index (ACWI) is a stock index designed to provide a broad measure of global equity market performance.

Index ETF: Definition, Types, Advantages, and Risks

Index ETFs are exchange-traded funds that seek to track a benchmark index like the S&P 500 as closely as possible.

S&P 500 Index: What It’s for and Why It’s Important in Investing

The S&P 500 Index (Standard & Poor's 500 Index) is a market-capitalization-weighted index of the 500 leading publicly traded companies in the U.S.

How to Benchmark Your ETF Investments

Exchange-Traded Product (ETP) vs. Exchange-Traded Fund (ETF): What’s the Difference?

ETFs vs. Index Mutual Funds: What's the Difference?

How to Use Benchmarks in Investing

Market Index: Definition, How Indexing Works, Types, and Examples

Indexing: Definition and Uses in Economics and Investing

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Indices vs. Indexes

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Indices vs. Indexes

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Indices vs. Indexes"Indices" is frequently used wrongly in various phrases, presentations and speeches, because it is often confused for "indexes". Some think these words refer to the same thing and therefore replace them even when it's not appropriate.Two letters spelled differently inside two distinct words can count a lot, and they do for "indices" and "indexes" even though these words are still very similar. Find out what each word represents and what the limits are, that allow you to use "indices" instead of "indexes".Indices vs. IndexesYes, "indices" is defined the same as "indexes" in a particular case, but only there. Apart from that, "indexes" has a bigger number of meanings and can be used in more contexts than "indices". Let's take a closer look to these.When do we use "indices"?"Indices" is a plural noun, one of the plural forms for "index", but only in a particular situation: when "index" refers to a system. "Indices" and "indexes" can refer to systems for recording changes and comparing values, usually in the financial domain. This is the only context where "indices" and "indexes" are synonyms, as well as the only situation where using "indices" is recommended.Example: The price indices have registered a significant growth the last year. - "indices" refers to some elements in a financial system of comparing and recording values and their changes.When do we use "indexes"?Unlike "indices", which is limited to the meaning presented above, "indexes" represents the plural of "index" with a lot more significations. First, as a noun, "indexes" can define alphabetical lists of subjects, names, titles etc., usually in the last pages of a book, indicating the page where each title can be found. Secondly, it can also define a collection of data stored in a computer ordered alphabetically.Nonetheless, as a noun, "indexes" can be synonym with "indices" (explained above), or can also be used when referring to more index fingers (the fingers next to the thumbs).Eventually, "index" is also a verb referring to the action of arranging information in an index (in an alphabetically ordered list). Therefore, "indexes" can also be used as the singular third person present simple of this verb.Example 1: Indexes usually contain every chapter title of a book and the page where you can find them. - referring to the list of alphabetically ordered titles in a book.Example 2: Indexes of all our programs contain all the data you need. - alphabetically ordered collections of data stored in programs.Example 3: The price indexes have registered a growing tendency during the last two years. - used with the same meaning as "indices" (explained above).Example 4: Wearing rings on your indexes does not mean you are engaged or married. - referring to the index fingers.Example 5: He indexes new titles on a daily basis, in the list of recently published books. - defining the action of arranging information in an index.ConclusionAs you can see, "indexes" has numerous possibilities of use, in several contexts and with distinct meanings, whereas "indices" is only synonym with "indexes" when it refers to a particular meaning. Remember this limitation in order to always use these words correctly and never replace one with another in a situation that would change your message completely.

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Meaning of index in English

indexnoun uk

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/ˈɪn.deks/ us

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/ˈɪn.deks/ plural indices uk/ˈɪn.dɪ.siːz/ us/ˈɪn.də.siːz/ indexes

index noun

(LIST)

Add to word list

C1 [ C ] an alphabetical list, such as one printed at the back of a book showing which page a subject, name, etc. is on: in the index Try looking up "heart disease" in the index.

[ C ] a collection of information stored on a computer or on a set of cards, in alphabetical order: on a card index He still has all his friends' names and addresses on a card index.

More examplesFewer examplesThe index is divided into two sections.He got one of his research assistants to compile the index.The index only contains one reference to his work.The thesis must include an index and a bibliography.Using the index would have saved you a lot of time.

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index noun

(COMPARISON)

[ C ] a system of numbers used for comparing values of things that change according to each other or a fixed standard: the FTSE 100 Index the Dow Jones Index a wage/price index

[ C usually singular ] something that shows how strong or common a condition or feeling is: index of Consumer spending is often a good index of public confidence in the economy.

More examplesFewer examplesGood economic indicators caused the share index to gain (by) ten points.The index only includes companies that are based in the UK.The index measures the rise and fall of stock prices on the Hong Kong stock market.Traders can use stock index futures to limit the risk associated with changes in prices.The heat index is a measure of how hot the air feels.

SMART Vocabulary: related words and phrases

Numerical relationships

absolute maximum

absolute minimum

arithmetic progression

cardinality

commensurable

differential

golden ratio

harmonic progression

intersect

inverse function

inverse proportion

iteration

proportion

proportional

proportionately

prorate

prorated

quantile

rank correlation

subset

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Statistics

indexverb [ T ] uk

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/ˈɪn.deks/ us

Your browser doesn't support HTML5 audio

/ˈɪn.deks/

index verb [T]

(MAKE LIST)

to prepare an index for a book or collection, or arrange it in an index: Our computer indexes several thousand new records every second. The book contains a lot of information, but it's not very well indexed.

SMART Vocabulary: related words and phrases

Editing & compiling

abridged

amend

anthologist

blue pencil

bowdlerization

bowdlerized

co-edit

compile

excerpt

non-editorial

over-edit

post-editing

proofreading

recension

revise

subedit

undubbed

unfiltered

unindexed

unrevised

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index verb [T]

(COMPARE)

to change a system of numbers according to each other or a fixed standard: be indexed to/in line with Living expenses will be indexed to/in line with inflation (= to take inflation into consideration).

SMART Vocabulary: related words and phrases

Estimating value

appraise

appraiser

book value

buying power

cost

costing

de-index

dollar sign

est.

euro

index of leading economic indicators

pricelessly

pricing

put a figure on it idiom

put something at something

quantity surveyor

quote

re-estimate

recommended retail price

underestimate

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(Definition of index from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)

index | American Dictionary

indexnoun [ C ] us

Your browser doesn't support HTML5 audio

/ˈɪn·deks/ plural indexes us/ˈɪnˌdek·səz/ indices us/ˈɪn·dəˌsiz/

index noun [C]

(LIST)

Add to word list

writing an alphabetical list, such as one printed at the back of a book showing on which page a name or subject appears, or computer information ordered in a particular way: If you want to find the place in the text that Henry James is mentioned, look it up in the index.

index noun [C]

(COMPARISON)

a number used to show the value of something by comparing it to something else whose value is known: a wage/price index fig. The rate of consumer spending is often thought to be an index of public confidence (= show the state of the public’s confidence) in the health of the economy.

indexverb [ T ] us

Your browser doesn't support HTML5 audio

/ˈɪn·deks/

index verb [T]

(MAKE LIST)

to prepare an index for a book, or to arrange information in an index: He organized and indexed the material by computer.

index verb [T]

(MAKE COMPARISON)

to vary a system of numbers against another or against a fixed standard: Social Security payments are indexed to (= adjusted to allow for) inflation every year.

(Definition of index from the Cambridge Academic Content Dictionary © Cambridge University Press)

index | Business English

indexnoun [ C ] uk

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/ˈɪndeks/ us

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Add to word list

FINANCE, ECONOMICS

plural indices | indexes a system that measures the present value of something when compared to its previous value or a fixed standard: The house price index estimates the change in the value of the nation's housing stock. a bond/share/stock indexan index of sth The fund tracks an index of the UK's top 350 UK shares.

plural indices a sign or measure of something: an index of sth Unemployment levels provide a useful index of the state of the economy.

plural indexes an alphabetical list that shows you where information is found in a book, on a website, etc.: a searcheable index online indexes to articles and reports

plural indexes a collection of information that is stored in alphabetical order: I keep an index of all my clients' contact details.

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U.S. markets closedS&P 5005,175.27+57.33(+1.12%)Dow 3039,005.49+235.83(+0.61%)Nasdaq16,265.64+246.36(+1.54%)Russell 20002,065.48-0.40(-0.02%)Crude Oil78.03+0.10(+0.13%)Gold2,163.90-24.70(-1.13%)World IndicesSymbolNameLast PriceChange% ChangeVolumeIntraday High/Low52 Week RangeDay Chart^GSPCS&P 5005,175.27+57.33+1.12%2.294B^DJIDow Jones Industrial Average39,005.49+235.83+0.61%334.748M^IXICNASDAQ Composite16,265.64+246.36+1.54%4.533B^NYANYSE COMPOSITE (DJ)17,974.06+110.37+0.62%0^XAXNYSE AMEX COMPOSITE INDEX4,694.35+19.21+0.41%0^BUK100PCboe UK 100775.93+8.01+1.04%0^RUTRussell 20002,065.48-0.40-0.02%0^VIXCBOE Volatility Index13.84-1.38-9.07%0^FTSEFTSE 1007,747.81+78.58+1.02%0^GDAXIDAX PERFORMANCE-INDEX17,965.11+218.84+1.23%0^FCHICAC 408,087.48+67.75+0.84%0^STOXX50EESTX 50 PR.EUR4,983.20+52.78+1.07%0^N100Euronext 100 Index1,491.54+12.46+0.84%0^BFXBEL 203,749.94+8.23+0.22%0IMOEX.MEMOEX Russia Index2,222.51-4.14-0.19%0^N225Nikkei 22538,797.51-22.98-0.06%0^HSIHANG SENG INDEX17,093.50+505.93+3.05%0000001.SSSSE Composite Index3,055.94-12.52-0.41%2.92B399001.SZShenzhen Index9,630.54+49.01+0.51%176.342M^STISTI Index3,141.47+3.05+0.10%0^AXJOS&P/ASX 2007,712.50+8.30+0.11%0^AORDALL ORDINARIES7,973.00+9.40+0.12%0^BSESNS&P BSE SENSEX73,667.96+165.32+0.22%0^JKSEIDX COMPOSITE7,381.91-7,373.96-49.97%0^KLSEFTSE Bursa Malaysia KLCI1,554.56+9.85+0.64%0^NZ50S&P/NZX 50 INDEX GROSS ( GROSS 11,828.65-0.53-0.00%0^KS11KOSPI Composite Index2,681.81+21.97+0.83%0^TWIITSEC weighted index19,914.55+188.47+0.96%0^GSPTSES&P/TSX Composite index21,831.02+61.80+0.28%212.992M^BVSPIBOVESPA127,667.84+1,544.28+1.22%0^MXXIPC MEXICO54,898.95-177.17-0.32%203.211M^IPSAS&P/CLX IPSA5,058.880.000.00%0^MERVMERVAL38,390.84+233.89+0.61%0^TA125.TATA-1251,933.72-10.92-0.56%0^CASE30EGX 30 Price Return Index32,661.60-720.90-2.16%249.441M^JN0U.JOTop 40 USD Net TRI Index3,869.05-1.00-0.03%0

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k Market Indexes - Google FinanceFinanceSign inFinanceFinancefinance_modeHomemanage_searchMarket trendsPortfoliosaddCreate portfolioWatchlistsaddCreate watchlistsettingsSettingsfeedbackSend feedbackMarketsUSEuropeAsiaCurrenciesCryptoFuturesNikkei 22538,797.51-0.059%-22.98Nikkei 22538,797.510.059%SSE3,055.94-0.41%-12.52SSE3,055.940.41%HSI17,093.50+3.05%+505.93HSI17,093.503.05%SENSEX73,667.96+0.22%+165.32SENSEX73,667.960.22%NIFTY 5022,335.70+0.014%+3.05NIFTY 5022,335.700.014%Explore market trendsShareMarket indexesMost activeGainersLosersClimate leadersCryptoCurrenciesAmericasMorechevron_rightIndexS&P 5005,175.27+57.331.12%add_circle_outlineIndexDow Jones Industrial Average39,005.49+235.830.61%add_circle_outlineIndexNasdaq Composite16,265.64+246.361.54%add_circle_outlineIndexRussell 2000 Index2,065.48-0.400.020%add_circle_outlineIndexS&P/TSX Composite Index21,831.02+61.800.28%add_circle_outlineIndexIBOVESPA127,667.84+1,544.281.22%add_circle_outlineEurope, Middle East, and AfricaMorechevron_rightIndexDAX PERFORMANCE-INDEX17,965.11+218.841.23%add_circle_outlineIndexFTSE 100 Index7,747.81+78.581.02%add_circle_outlineIndexCAC 408,087.48+67.750.84%add_circle_outlineIndexIBEX 3510,388.90+63.200.61%add_circle_outlineIndexEURO STOXX 504,983.20+52.781.07%add_circle_outlineIndexS&P EURO2,149.27+21.251.00%add_circle_outlineAsia PacificMorechevron_rightIndexNikkei 22538,797.51-22.980.059%add_circle_outlineIndexSSE Composite Index3,055.94-12.520.41%add_circle_outlineIndexHang Seng Index17,093.50+505.933.05%add_circle_outlineIndexBSE SENSEX73,667.96+165.320.22%add_circle_outlineIndexNIFTY 5022,335.70+3.050.014%add_circle_outlineIndexS&P Asia 504,784.84+108.192.31%add_circle_outlineIn the newsBased on marketsCNBC1 day agoS&P 500 closes lower for a second session as tech-fueled rally cools: Live

updates.INX1.12%S&P 500Yahoo Finance1 hour agoStock market today: S&P 500 hits new record high as investors shrug off

sticky inflation data.INX1.12%S&P 500Investopedia2 hours agoDow Jones Today: Nasdaq Charges Higher, Yields Jump Following Inflation DataNDAQ0.48%Nasdaq Inc.DJI0.61%Dow Jones Industrial AverageCNBC4 hours agoDow jumps 100 points, Nasdaq gains 1% as Nvidia, tech shares resume rally:

Live updatesCNBC4 hours agoEuropean markets close higher following U.S. inflation data; FTSE 100 hits

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Indexing in DBMS: What is, Types of Indexes with EXAMPLES

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Indexing in DBMS: What is, Types of Indexes with EXAMPLES

By :

Richard Peterson

Hours

UpdatedMarch 9, 2024

What is Indexing?

Indexing is a data structure technique which allows you to quickly retrieve records from a database file. An Index is a small table having only two columns. The first column comprises a copy of the primary or candidate key of a table. Its second column contains a set of pointers for holding the address of the disk block where that specific key value stored.

An index –

Takes a search key as input

Efficiently returns a collection of matching records.

Table of Content:What is Indexing?Types of Indexing in DBMSPrimary Index in DBMSSecondary Index in DBMSClustering Index in DBMSWhat is Multilevel Index?B-Tree IndexAdvantages of IndexingDisadvantages of IndexingSummary

Types of Indexing in DBMS

Type of Indexes in Database

Indexing in Database is defined based on its indexing attributes. Two main types of indexing methods are:

Primary Indexing

Secondary Indexing

Primary Index in DBMS

Primary Index is an ordered file which is fixed length size with two fields. The first field is the same a primary key and second, filed is pointed to that specific data block. In the primary Index, there is always one to one relationship between the entries in the index table.

The primary Indexing in DBMS is also further divided into two types.

Dense Index

Sparse Index

Dense Index

In a dense index, a record is created for every search key valued in the database. This helps you to search faster but needs more space to store index records. In this Indexing, method records contain search key value and points to the real record on the disk.

Sparse Index

It is an index record that appears for only some of the values in the file. Sparse Index helps you to resolve the issues of dense Indexing in DBMS. In this method of indexing technique, a range of index columns stores the same data block address, and when data needs to be retrieved, the block address will be fetched.

However, sparse Index stores index records for only some search-key values. It needs less space, less maintenance overhead for insertion, and deletions but It is slower compared to the dense Index for locating records.

Below is an database index Example of Sparse Index

Secondary Index in DBMS

The secondary Index in DBMS can be generated by a field which has a unique value for each record, and it should be a candidate key. It is also known as a non-clustering index.

This two-level database indexing technique is used to reduce the mapping size of the first level. For the first level, a large range of numbers is selected because of this; the mapping size always remains small.

Secondary Index Example

Let’s understand secondary indexing with a database index example:

In a bank account database, data is stored sequentially by acc_no; you may want to find all accounts in of a specific branch of ABC bank.

Here, you can have a secondary index in DBMS for every search-key. Index record is a record point to a bucket that contains pointers to all the records with their specific search-key value.

Clustering Index in DBMS

In a clustered index, records themselves are stored in the Index and not pointers. Sometimes the Index is created on non-primary key columns which might not be unique for each record. In such a situation, you can group two or more columns to get the unique values and create an index which is called clustered Index. This also helps you to identify the record faster.

Example:

Let’s assume that a company recruited many employees in various departments. In this case, clustering indexing in DBMS should be created for all employees who belong to the same dept.

It is considered in a single cluster, and index points point to the cluster as a whole. Here, Department _no is a non-unique key.

What is Multilevel Index?

Multilevel Indexing in Database is created when a primary index does not fit in memory. In this type of indexing method, you can reduce the number of disk accesses to short any record and kept on a disk as a sequential file and create a sparse base on that file.

B-Tree Index

B-tree index is the widely used data structures for tree based indexing in DBMS. It is a multilevel format of tree based indexing in DBMS technique which has balanced binary search trees. All leaf nodes of the B tree signify actual data pointers.

Moreover, all leaf nodes are interlinked with a link list, which allows a B tree to support both random and sequential access.

Lead nodes must have between 2 and 4 values.

Every path from the root to leaf are mostly on an equal length.

Non-leaf nodes apart from the root node have between 3 and 5 children nodes.

Every node which is not a root or a leaf has between n/2] and n children.

Advantages of Indexing

Important pros/ advantage of Indexing are:

It helps you to reduce the total number of I/O operations needed to retrieve that data, so you don’t need to access a row in the database from an index structure.

Offers Faster search and retrieval of data to users.

Indexing also helps you to reduce tablespace as you don’t need to link to a row in a table, as there is no need to store the ROWID in the Index. Thus you will able to reduce the tablespace.

You can’t sort data in the lead nodes as the value of the primary key classifies it.

Disadvantages of Indexing

Important drawbacks/cons of Indexing are:

To perform the indexing database management system, you need a primary key on the table with a unique value.

You can’t perform any other indexes in Database on the Indexed data.

You are not allowed to partition an index-organized table.

SQL Indexing Decrease performance in INSERT, DELETE, and UPDATE query.

Summary

Indexing is a small table which is consist of two columns.

Two main types of indexing methods are 1)Primary Indexing 2) Secondary Indexing.

Primary Index is an ordered file which is fixed length size with two fields.

The primary Indexing is also further divided into two types 1)Dense Index 2)Sparse Index.

In a dense index, a record is created for every search key valued in the database.

A sparse indexing method helps you to resolve the issues of dense Indexing.

The secondary Index in DBMS is an indexing method whose search key specifies an order different from the sequential order of the file.

Clustering index is defined as an order data file.

Multilevel Indexing is created when a primary index does not fit in memory.

The biggest benefit of Indexing is that it helps you to reduce the total number of I/O operations needed to retrieve that data.

The biggest drawback to performing the indexing database management system, you need a primary key on the table with a unique value.

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What Is a Market Index?

How It Works

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Market Index: Definition, How Indexing Works, Types, and Examples

Julie Young

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Julie Young is an experienced financial writer and editor. She specializes in financial analysis in capital planning and investment management.

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Investopedia / Yurle Villegas

What Is a Market Index?

A market index is a hypothetical portfolio of investment holdings that represents a segment of the financial market. The calculation of the index value comes from the prices of the underlying holdings. Some indexes have values based on market-cap weighting, revenue weighting, float weighting, and fundamental weighting. Weighting is a method of adjusting the individual impact of items in an index.

Investors follow different market indexes to gauge market movements. The three most popular stock indexes for tracking the performance of the U.S. market are the Dow Jones Industrial Average (DJIA), S&P 500 Index, and Nasdaq Composite Index. In the bond market, Bloomberg is a leading provider of market indexes with the Bloomberg U.S. Aggregate Bond Index serving as one of the most popular proxies for U.S. bonds. Investors cannot invest directly in an index, so these portfolios are used broadly as benchmarks or for developing index funds.

Key Takeaways

Market indexes provide a broad representative portfolio of investment holdings.Methodologies for constructing individual indexes vary but nearly all calculations are based on weighted average mathematics.Indexes are used as benchmarks to gauge the movement and performance of market segments.Investors use indexes as a basis for portfolio or passive index investing.

Understanding a Market Index

A market index measures the value of a portfolio of holdings with specific market characteristics. Each index has its own methodology which is calculated and maintained by the index provider. Index methodologies will typically be weighted by either price or market cap.

A wide variety of investors use market indexes for following the financial markets and managing their investment portfolios. Indexes are deeply entrenched in the investment management business with funds using them as benchmarks for performance comparisons and managers using them as the basis for creating investable index funds.

Types of Market Indexes

Each individual index has its own method for calculating the index’s value. Weighted average mathematics is primarily the basis for index calculations as values are derived from a weighted average calculation of the value of the total portfolio.

As such, price-weighted indexes will be more greatly impacted by changes in holdings with the highest price, while market capitalization-weighted indexes will be most greatly impacted by changes in the largest stocks, and so on, depending on the weighting characteristics.

Market Indexes As Benchmarks

As a hypothetical portfolio of holdings, indexes act as benchmark comparisons for a variety of purposes across the financial markets. As mentioned, the Dow Jones, S&P 500, and Nasdaq Composite are three popular U.S. indexes.

These three indexes include the 30 largest stocks in the U.S. by market cap, the 500 largest stocks, and all of the stocks on the Nasdaq exchange, respectively. Since they include some of the most significant U.S. stocks, these benchmarks can be a good representation of the overall U.S. stock market.

Other indexes have more specific characteristics that create a more narrowly targeted market focus. For example, indexes can represent micro-sectors or maturity in the case of fixed income. Indexes can also be created to represent a geographic segment of the market such as those that track the emerging markets or stocks in the United Kingdom and Europe. The FTSE 100 is an example of such an index.

Investors may choose to build a portfolio with diversified exposure to several indexes or individual holdings from a variety of indexes. They may also use benchmark values and performance to follow investments by segment. Some investors will allocate their investment portfolios based on the returns or expected returns of certain segments. Further, a specific index may act as a benchmark for a portfolio or a mutual fund.

Index Funds

Institutional fund managers use benchmarks as a proxy for a fund’s individual performance. Each fund has a benchmark discussed in its prospectus and provided in its performance reporting, thus offering transparency to investors. Fund benchmarks can also be used to evaluate the compensation and performance of fund managers.

1884

The year the Dow Jones Railroad Average, a precursor to the Dow Jones Industrial Average, was published by Charles Dow. The average was composed of nine railway companies, a steamship company, and Western Union.

Institutional fund managers also use indexes as a basis for creating index funds. Individual investors cannot invest in an index without buying each of the individual holdings, which is generally too expensive from a trading perspective.

Therefore, index funds are offered as a low-cost way for investors to invest in a comprehensive index portfolio, gaining exposure to a specific market segment of their choosing. Index funds use an index replication strategy that buys and holds all of the constituents in an index. Some management and trading costs are still included in the fund’s expense ratio, but the costs are much lower than fees for an actively managed fund.

Examples of Market Indexes

Some of the market’s leading indexes include:

S&P 500

Dow Jones Industrial Average

Nasdaq Composite

S&P 100

Russell 1000

S&P MidCap 400

Russell Midcap

Russell 2000

S&P 600

U.S. Aggregate Bond Market

Global Aggregate Bond Market

Investors often choose to use index investing over individual stock holdings in a diversified portfolio. Investing in a portfolio of index funds can be a good way to optimize returns while balancing risk. For example, investors seeking to build a balanced portfolio of U.S. stocks and bonds could choose to invest 50% of their funds in an S&P 500 ETF and 50% in a U.S. Aggregate Bond Index ETF.

Investors may also choose to use market index funds to invest in emerging growth sectors. Some popular emerging growth indexes and corresponding exchange-traded funds (ETFs) include the following:

The iShares Global Clean Energy ETF (ICLN), which tracks the S&P Global Clean Energy Index

The Reality Shares Nasdaq NexGen Economy ETF (BLCN), which tracks the Reality Shares Nasdaq Blockchain Economy Index

The First Trust Nasdaq Artificial Intelligence and Robotics ETF (ROBT), which tracks the Nasdaq CTA Artificial Intelligence and Robotics Index

What Are the Major Stock Indexes?

In the United States, the three leading stock indexes are the Dow Jones Industrial Average, the S&P 500, and the Nasdaq Composite. For international markets, the Financial Times Stock Exchange 100 Index and the Nikkei 225 Index are popular proxies for the British and Japanese stock markets, respectively.

Why Are Indexes Useful to Investors?

Indexes provide investors with a simplified snapshot of a large market sector, without having to examine every single asset in that index. For example, it would be impractical for an ordinary investor to study hundreds of different stock prices in order to understand the changing fortunes of different technology companies; however, a sector-wide index like the NASDAQ-100 Technology Sector Index can show the average trend for the sector.

What Is the Most Widely Cited U.S. Stock Index?

The Dow Jones Industrial Average is the oldest U.S. stock index, as well as the most frequently cited one; however, the S&P 500 represents a larger cross-section of the economy.

The Bottom Line

Market indexes are hypothetical portfolios of investment holdings that investors use as an indicator of market movement. There are many different types of market indexes. Market indexes are also used to create index funds, allowing investors to buy a basket of securities rather than picking individual stocks.

Article Sources

editorial policy.

S&P Dow Jones Indices. "Dow Jones Industrial Average."

S&P Dow Jones Indices. "S&P 500."

NASDAQ. "NASDAQ Composite," Page 1.

FTSE Russell. "FTSE UK Index Series," Page 15.

Library of Congress. "Dow Jones Industrial Average First Published."

iShares by BlackRock. "2022 Prospectus - iShares Global Clean Energy ETF," Pages S-2.

U.S. Securities and Exchange Commission. "Reality Shares ETF Trust," Pages 1-2.

First Trust. "First Trust Nasdaq Artificial Intelligence and Robotics ETF (ROBT)."

NASDAQ. "NASDAQ-100 Technology Sector Index."

NASDAQ. "What Are the Three Most Quoted Stock Indexes?"

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Related Terms

MSCI All Country World Index (ACWI): Definition and Countries

The MSCI All Country World Index (ACWI) is a stock index designed to provide a broad measure of global equity market performance.

What Is an Index? Examples, How It's Used, and How to Invest

An index measures the performance of a basket of securities intended to replicate a certain area of the market, such as the Standard & Poor's 500.

CNX Nifty: Definition, How It Works, and History

The CNX Nifty is an index composed of 50 of the largest and most liquid stocks on the National Stock Exchange of India. It is commonly referred to as the Nifty 50.

S&P 500 Index: What It’s for and Why It’s Important in Investing

The S&P 500 Index (Standard & Poor's 500 Index) is a market-capitalization-weighted index of the 500 leading publicly traded companies in the U.S.

Index Rebalancing: What Every Investor Should Know

Index rebalancing involves changing the weights of index components to maintain its mandate or goal. This could include adding or dropping component assets.

What Is a Broad-Based Index, and What Are Some Broad Index Funds?

A broad-based index is designed to reflect the movement of the entire market—one example of a broad-based index is the Dow Jones Industrial Average.

How to Benchmark Your ETF Investments

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MSCI All Country World Index (ACWI): Definition and Countries

What Is an Index? Examples, How It's Used, and How to Invest

ETFs vs. Index Mutual Funds: What's the Difference?

How to Measure the Total Stock Market

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