You probably didn’t learn this in medical school, but choosing the right index fund can matter quite a bit for a physician’s long-term financial health. Both SWPPX (Schwab S&P 500 Index Fund) and VOO (Vanguard S&P 500 ETF) are low-cost ways to gain exposure to the US stock market’s large-cap sector, but they differ in a few key ways.
As we did when we compared FXAIX vs. VOO, this comparison of SWPPX vs. VOO will focus on practical differences for busy medical professionals. Let's look at how the two funds differ in their construction, expense ratios, and other intangibles.
What Is an S&P 500 Index Fund?
Before comparing SWPPX and VOO, it helps to understand about S&P 500 index funds. An S&P 500 index fund is designed to follow the performance of the S&P 500, one of the most widely used measures of the US stock market.
The S&P 500 is made up of 500 of the largest publicly traded companies in the United States. This includes familiar companies like Microsoft, Tesla, Amazon, Nvidia, Alphabet (Google), and Berkshire Hathaway. Instead of buying shares of all of these individual companies, you instead can buy a single S&P 500 mutual fund or ETF (such as SWPPX) and instantly own a small piece of all of them.
S&P 500 index funds are especially popular with long-term investors, including many doctors, because the index has historically returned about 10% per year on average over long periods of time.
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What Is SWPPX?
SWPPX is the ticker for the Schwab S&P 500 Index Fund, which is Schwab’s flagship S&P 500 mutual fund. It is designed to replicate the S&P 500 and serve as a core large-cap holding. It has a relatively low expense ratio (around 0.02%), which makes it one of the cheapest ways to hold the stocks in the S&P 500 index.
Unlike an ETF, SWPPX is a mutual fund. That means that it prices trades only once, at the end of the day. It also means that you can invest fractional dollar amounts, since there is no share-size requirement. SWPPX opened in 1997, and, as of January 2026, it has a 10-year annualized return of 14.78%, as compared to 14.82% for the S&P 500 index itself.
What Is VOO?
VOO is the ticker symbol for the Vanguard S&P 500 ETF. It is offered by Vanguard, the company best known for bringing index funds to everyday investors. VOO charges a low annual expense ratio of 0.03%.
Because VOO is an ETF as opposed to a mutual fund, it can be bought and sold throughout the trading day while the market is open. It has a strong reputation, earning a five-star Gold rating from Morningstar. The fund launched in 2010, and it has delivered strong long-term results, with a 10-year average return of 14.78% as of January 2026.
SWPPX vs. VOO: Which Should I Choose?
Choosing between SWPPX and VOO usually comes down to what’s easiest for you. SWPPX may be slightly cheaper, but when expense ratios are already this low, cost alone shouldn’t drive the decision. If you already invest at Schwab and prefer a traditional mutual fund, SWPPX is a solid option. If your accounts are already at Vanguard, VOO or its mutual fund version, VFIAX, may make more sense.
And if you specifically want an ETF instead of a mutual fund, VOO is the clear choice. In the end, these funds are extremely similar, and the differences are fairly small. Here were the numbers as of February 2026.
SWPPX vs. VOO: Which Is Better?
So, is VOO better than SWPPX? Is it the low-cost Vanguard ETF or the low-cost Schwab mutual fund? Both options can be the right choice, depending on your investment goals. The tax efficiency and the trading abilities of an ETF could give VOO an edge, but SWPPX has a slightly lower cost.
At the end of the day, both VOO and SWPPX are likely to be good choices for most long-term investors. You're not likely to regret choosing either of these funds as a long-term investment goal. As with most investment choices, the most important thing is to just start investing regularly. This will give you time for the magic of compounding interest to grow your portfolio's balance.
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The Bottom Line
Both SWPPX and VOO are excellent, low-cost ways for doctors and other medical professionals to invest in the US stock market. Since they track the same S&P 500 index, their long-term performance is nearly identical, and the small differences in expense ratios are unlikely to have a meaningful impact over time. The better choice usually comes down to convenience, account type, and personal preference. The most important thing is to just start investing with either fund.
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