S&P 500 Weights of Individual Companies 1979 – 2019

The table below lists the weightings of the largest S&P 500 index components. Currently (12/31/2019), the index components with the largest weightings are Apple Inc. (4.58%), Microsoft Corp. (4.50%), Amazon.com Inc (2.88%) & Facebook Inc (1.85%). Note that Alphabet Inc has two share classes part of the index, Class A (GOOGL) and Class C (GOOG). The combined weight of the both share lines is 2.99%.

For up-to-date data, check the datasets provided by Siblis Research.

S&P 500 – Weightings of the Largest Components (%)

Ticker ISIN Code Company Name 12/31/2019 12/31/2018 12/31/2017 12/31/2016 12/31/2015
AAPL US0378331005 Apple Inc. 4.58% 3.38% 3.81% 3.21% 3.28%
MSFT US5949181045 Microsoft Corp. 4.50% 3.73% 2.89% 2.51% 2.48%
AMZN US0231351067 Amazon.com Inc. 2.88% 2.93% 2.05% 1.54% 1.45%
FB US30303M1027 Facebook Inc. 1.85% 1.50% 1.85% 1.40% 1.33%
BRK.B US0846707026 Berkshire Hathaway Inc 1.66% 1.89% 1.67% 1.61% 1.38%
JPM US46625H1005 JPMorgan Chase & Co. 1.63% 1.54% 1.63% 1.60% 1.36%
GOOGL US02079K3059 Alphabet Inc. Class A 1.50% 1.49% 1.38% 1.22% 1.27%
GOOG US02079K1079 Alphabet Inc. Class C 1.49% 1.52% 1.39% 1.19% 1.26%
JNJ US4781601046 Johnson & Johnson 1.43% 1.65% 1.65% 1.63% 1.59%
V US92826C8394 Visa Inc. 1.20% 1.10% 0.91% 0.76% 0.84%
PG US7427181091 Procter & Gamble Co 1.16% 1.09% 1.03% 1.17% 1.21%
XOM US30231G1022 Exxon Mobil Corp. 1.10% 1.37% 1.55% 1.94% 1.81%
T US00206R1023 AT&T Inc. 1.07% 0.99% 1.05% 1.36% 1.18%
BAC US0605051046 Bank of America Corp. 1.07% 1.07% 1.26% 1.16% 0.98%
UNH US91324P1021 UnitedHealth Group Inc 1.04% 1.14% 0.94% 0.79% 0.63%
MA US57636Q1040 Mastercard Inc. 0.99% 0.82% 0.62% 0.51% 0.54%
DIS US2546871060 Walt Disney Co 0.97% 0.78% 0.71% 0.79% 0.89%
INTC US4581401001 Intel Corp. 0.97% 1.02% 0.95% 0.89% 0.91%
VZ US92343V1044 Verizon Communications Inc 0.95% 1.11% 0.95% 1.13% 1.05%
HD US4370761029 Home Depot Inc 0.89% 0.92% 0.97% 0.85% 0.94%
MRK US58933Y1055 Merck & Co Inc 0.87% 0.95% 0.67% 0.84% 0.82%
CVX US1667641005 Chevron Corp. 0.85% 0.99% 1.04% 1.15% 0.95%
PFE US7170811035 Pfizer Inc. 0.81% 1.20% 0.95% 1.02% 1.11%
KO US1912161007 The Coca Cola Co. 0.80% 0.86% 0.77% 0.84% 0.94%
WFC US9497461015 Wells Fargo & Co 0.77% 0.93% 1.18% 1.29% 1.41%
CMCSA US20030N1019 Comcast Corp Class A 0.76% 0.74% 0.82% 0.85% 0.77%
CSCO US17275R1023 Cisco Systems Inc 0.76% 0.93% 0.83% 0.79% 0.77%
PEP US7134481081 PepsiCo Inc. 0.71% 0.74% 0.75% 0.78% 0.81%
C US1729674242 Citigroup Inc. 0.65% 0.60% 0.86% 0.88% 0.86%
BA US0970231058 Boeing Co. 0.65% 0.81% 0.72% 0.46% 0.51%
WMT US9311421039 Wal-Mart Stores Inc 0.63% 0.63% 0.63% 0.54% 0.54%
ADBE US00724F1012 Adobe Systems Inc. 0.60% 0.53% 0.38% 0.27% 0.26%
ABT US0028241000 Abbott Laboratories 0.57% 0.60% 0.44% 0.29% 0.37%
MDT IE00BTN1Y115 Medtronic PLC 0.57% 0.58% 0.48% 0.51% 0.60%
BMY US1101221083 Bristol-Myers Squibb Co 0.56% 0.40% 0.44% 0.51% 0.64%
MCD US5801351017 McDonald's Corp. 0.56% 0.65% 0.60% 0.52% 0.61%
CRM US79466L3024 Salesforce.com Inc 0.54% 0.50% 0.31% 0.23% 0.27%
NVDA US67066G1040 Nvidia Corp. 0.54% 0.39% 0.51% 0.30% 0.09%
AMGN US0311621009 Amgen Inc. 0.54% 0.59% 0.55% 0.56% 0.68%
NFLX US64110L1061 Netflix Inc. 0.53% 0.56% 0.36% 0.28% 0.27%
ACN IE00B4BNMY34 Accenture plc 0.50% 0.43% 0.41% 0.38% 0.37%
PM US7181721090 Philip Morris International Inc 0.49% 0.49% 0.72% 0.74% 0.76%
ABBV US00287Y1091 AbbVie Inc. 0.49% 0.66% 0.68% 0.53% 0.54%
TMO US8835561023 Thermo Fisher Scientific Inc 0.49% 0.43% 0.33% 0.29% 0.32%
COST US22160K1051 Costco Wholesale Corp 0.49% 0.42% 0.36% 0.36% 0.40%
PYPL US70450Y1038 PayPal Holdings Inc. 0.47% 0.47% 0.36% 0.23% 0.23%
HON US4385161066 Honeywell International Inc 0.47% 0.47% 0.51% 0.46% 0.45%
NKE US6541061031 Nike Inc. 0.47% 0.45% 0.36% 0.35% 0.47%
AVGO US11135F1012 Broadcom Ltd 0.47% 0.50% 0.46% 0.37% 0.21%
UNP US9078181081 Union Pacific Corp 0.47% 0.48% 0.46% 0.44% 0.37%

Need access to full historical data? Purchase the exact weightings of the current and past S&P 500 companies since 1979. The weightings are available on a monthly basis since 12/31/2004 and for the last day of each quarter since 3/31/1979. Check a sample file from here.


For key historical data of the index companies, purchase the S&P 500 Researcher Dataset by Siblis Research which provides share prices, earnings, revenues, outstanding shares, market caps, enterprise values, P/E & P/B ratios and EV/EBITDA multiples of all current & past S&P 500 companies since 3/31/1979. The dataset provides also adjusted share prices (total returns) which allows you to examine the performance of the companies before/during/after a company was part of the index. Download a sample dataset from here.


Weightings of S&P 500 Companies

How the component weights are assigned?

S&P 500 index is free-float market capitalization weighted. So what does this mean? Let’s first define capitalization weighted index. This means that companies with higher market value have a larger weight in the index. So the changes in the stock prices of these components have a larger effect to the index value than price changes of less valuable companies.

Free-float weighted means that instead of full market cap, only the public float of the company is considered when calculating its weight. Not all the shares of a company can be traded freely but some stocks might be under restrictions from SEC. S&P Dow Jones is assigning IWF (Investable Weight Factor) for all components part of its US indexes based on the component’s float. Read more about public float of US corporations and IWF methodology of S&P Dow Jones from here.

Let’s take Apple as an example. Apple does not have any restricted stocks so it’s free float is the same as its market cap. This means that the firms IWF is 1. Apple’s market cap in Dec 31st 2016 was $586,859.3 million. When the float adjusted market caps of all the companies part of S&P 500 are summed together, the total adjusted index value was around $18,000,221 million during the same day. So at the end of December, Apple’s weight is $586,859.3 divided by $18,000,221 that equals 3.26%.

What is the effect of one component to the index value?

If you know the weight of an index component, it is very simple to calculate its effect to the overall index value. If the weight of a company is 1.00% of the index and the company’s stock price increases by 5%, the index price will increase 1% * 5% = 0.05%. The same calculation works if the price decreases, -5% dip in price would mean that the index value will drop 0.05%. Of course in real life the prices of all the components keep changing at the same.

Companies with multiple share classes

Based on the new rules for S&P Dow Jones’ US Indices, it is now possible for a company to have multiple share classes part of S&P 500. That is why the amount of components in the index is larger than 500. But how the weightings of the different stock lines are calculated?

Let’s take Google (now known as Alphabet) as an example. In April 3rd 2014, Google split its A-class stock into two classes, A and C. S&P Dow Jones first announced that new C Class will replace the old component but later reverted its previous announcement and declared that both classes will be included to S&P 500.

In Dec 31st 2015, GOOGL (A class) had around 265.11 million freely traded shares outstanding. GOOGL’s closing price was $778.01. GOOG (C Class) had 345.50 million freely traded shares outstanding and closed at $758.88. When calculating adjusted market caps and dividing them with the total index value, you will get the weights 1.15% and 1.46%. In Dec 2013 (before the split), the weight of A Class share was around 1.80%.

The change to float adjusted methodology

The weight of S&P 500 have not always been float adjusted. Before 2005, there were not weight factors and the index was pure capitalization weighted. But after receiving a lot feedback from fund managers and other institutional investors, S&P Dow Jones decided to change the index rules. The transition happened in two steps during 2005. During the first transition period, only half of the effect of weight factors was considered. For example, if a company had an IWF of 0.80, it was converted to 0.90. After the transition period ended in September 16th, weight factors were fully implemented.

Changes in sector weightings

Since May 2008, Information Technology has been the largest sector of the index. The global financial crisis of 2008 dropped Financials sectors from 1st place to 3rd largest sector. The financial companies quickly recovered part of their value and rose to 2nd biggest sector but has not been able to overtake IT. Download raw data for sector weights from here.

S&P 500 Equal Weight Index (Ticker: SPW)

There exists also another version of S&P 500 index where all companies have the same fixed weight, 0.2%. The components of this index are the same as with the float adjusted index. The smaller components have a much larger influence to the index value on the equal weight index (EWI).

EWI was launched on January 8th 2003. Since 2010, the returns from EWI have been larger than from the main S&P 500 but also volatility has been bigger. Especially during 2013, investors generated considerable bigger profit from equal weighted index.

The largest sector of the index is Financials (17.8%), Consumer Discretionary (16.7%) and Information Technology (14%). The smaller sector is Telecom Services with weight only 1.0%.

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