What is the difference between SPX vs SPY? SPX is the ticker symbol for the S&P 500 stock market index, whereas SPY is an ETF (exchange traded fund) that tracks the S&P 500 (SPX) index. You can buy shares of SPY but since SPX is an index it cannot be bought and sold.
What is a Stock Market Index?
Before we take a look at SPX vs SPY we’ll need to cover the basics. First up, a quick definition: In simple terms, the US stock market refers to the 7,000 or so companies that are publicly traded in the US.
A stock market index is a hypothetical portfolio comprised of a subset of those companies, and they are usually related in some way. While there are thousands of stock market indexes, the three main indexes are as follows:
What is the Purpose of a Stock Market Index?
Stock market indexes provide a way to easily understand the performance of the stock market, or sectors within the stock market. The S&P 500 Index is widely regarded as the best indicator of the performance of the entire US stock market. An index is sometimes based on the most important or relevant companies in the stock market (as is the case with the S&P 500), or within the sector being tracked.
What is the S&P 500 SPX Index? How is SPX Calculated?
Two important components of the SPX index are as follows:
What is the SPY ETF? How are SPX and SPY Related?
SPY is the ticker symbol for the SPDR S&P 500 ETF Trust. It was established in 1993 and is managed by State Street Global Advisors. In the following simple breakdown of SPX vs SPY, you’ll see the similarities between the two.
SPX Breakdown
Although the SPX index is comprised of 500 companies, for the purposes of this explanation, we’ll look at the ‘weighting’ of just the 3 largest companies in the SPX index. At the time of writing:
SPY Breakdown
Now, let’s take a look at the SPY ETF. The total value of the SPY exchange traded fund is approximately $380B, meaning it owns $380 billion in shares of the largest 500 publicly traded companies. Of that $380B, the largest 3 companies in the fund are as follows:
You can see that the value of shares owned by the fund tracks the weighting of those companies in the index. So, when the value of the SPX increases or decreases, so does the value of the SPY fund.
Why Invest in SPY?
A key advantage of owning SPY is its very low expense ratio (the cost of managing the fund). SPY is considered a ‘passively’ managed fund. Since it tracks the S&P 500, the fund manager does not have to make decisions or undertake complex calculations to know when to buy and sell stocks within the fund. This results in very low management costs. Stocks within SPY are ‘rebalanced’ (bought and sold) every quarter, to match the SPX index.
You can buy and sell shares in SPY easily just like any other stock. You could use an online broker such as E-Trade, a face-to-face broking service such as Merrill Lynch, or an automated robo-advisor such as Betterment.
Investing in SPY, or any index fund has many other advantages:
Wrapping Up
When trying to understand SPX vs SPY, remember that SPX is the S&P 500 index, whereas SPY is an ETF that tracks the index. SPY and other index funds are a core staple of many investors’ portfolios. They are an easy and effective way of providing solid returns in the long term.
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