When you're building a long-term investment portfolio, keeping fees as low as possible makes a massive difference over decades of compounding. Vanguard’s Total Stock Market Index Fund (VTSAX) stands as a legendary choice for passive investors seeking broad exposure to the entire U.S. stock market. But if your accounts live at Fidelity, buying VTSAX directly incurs transaction fees or isn't practical depending on your brokerage setup. You need a direct alternative within Fidelity's own ecosystem that matches its ultra-low expense ratio and broad diversification.
The exact equivalent to VTSAX inside Fidelity's lineup is FSKAX (Fidelity Total Market Index Fund). Both funds track the same underlying index performance, capturing thousands of large, mid, and small-cap U.S. companies. Understanding how these funds compare, how their fee structures match up, and why you might choose an exchange-traded fund (ETF) version instead will help you construct a clean, low-maintenance portfolio without ever leaving your preferred broker.
Understanding the Core Comparison: VTSAX vs. FSKAX
VTSAX tracks the CRSP US Total Market Index, while FSKAX tracks the Dow Jones U.S. Total Stock Market Index. Despite tracking different underlying indices provided by different indexing companies, their performance profiles look nearly identical. Both capture roughly 3,500 to 4,000 U.S. stocks, meaning you get exposure to tech giants alongside small regional banks and manufacturing firms in nearly identical proportions.
The primary difference lies in the minimum investment requirements and the brokerage ecosystem. VTSAX requires a minimum initial investment of $3,000 if purchased directly through Vanguard, though this barrier disappears if you buy its ETF sibling, VTI. Fidelity sets a remarkably friendly entry point for FSKAX: $0 minimum initial investment. You can start investing with five dollars, making FSKAX exceptionally accessible for beginners or automated weekly contributions.
Expense Ratios and Cost Efficiency
Fees eat away at your returns silently year after year. Both Vanguard and Fidelity compete fiercely on price, driving index fund costs down to nearly zero.
VTSAX carries an expense ratio of 0.04%, meaning you pay four dollars annually for every $10,000 invested. FSKAX matches this aggressive pricing with an expense ratio of 0.015%, making it even slightly cheaper. On a $10,000 balance, the difference amounts to just $2.50 per year—an essentially negligible gap. Both funds achieve this by eliminating human fund managers, relying instead on computerized tracking of their respective benchmarks.
Beyond expense ratios, watch out for transaction fees. Buying Vanguard mutual funds in a Fidelity brokerage account often triggers non-network transaction fees. Sticking to Fidelity proprietary funds like FSKAX inside a Fidelity account ensures zero trading commissions and zero account maintenance fees.
Mutual Funds vs. ETFs: Choosing the Right Vehicle
Deciding between a mutual fund like FSKAX and an exchange-traded fund introduces another layer to your strategy. While VTSAX has an ETF equivalent in VTI, Fidelity offers ITOT (iShares Core S&P Total U.S. Stock Market ETF) or its own proprietary ETFs, though many Fidelity loyalists simply stick to mutual funds for automated investing.
Mutual funds like FSKAX trade only once per day after the market closes. When you place a buy order at 10:00 AM, your transaction executes at the closing Net Asset Value (NAV) price. ETFs trade throughout the day like individual stocks. If you prefer setting up recurring, automated Monday-morning purchases of exact dollar amounts (fractional shares), mutual funds win on convenience. If you want intraday liquidity, ETFs fit better.
For most long-term buy-and-hold investors using a taxable brokerage account, tax efficiency matters. Historically, ETFs structure capital gains distributions more efficiently than mutual funds, preventing unexpected tax bills. However, Vanguard holds a unique patent structure where their broad index mutual funds share a tax class with their corresponding ETFs, minimizing capital gains distributions. Fidelity mutual funds don't share this exact structure, though index funds generally distribute very few capital gains anyway due to low portfolio turnover. You can learn more about regulatory guidelines directly from the U.S. Securities and Exchange Commission.
Common Mistakes When Pairing Funds Across Brokers
Investors frequently run into trouble by mixing fund families inefficiently. Trying to buy VTSAX inside a Fidelity taxable brokerage account usually triggers a substantial transaction fee because Vanguard is an outside institution. Always match your fund to your broker: use Vanguard for Vanguard funds, and use Fidelity equivalents for Fidelity accounts.
Another frequent error involves chasing past performance. FSKAX and VTSAX will never yield identical decimal returns because their underlying index providers track slightly different segments of the micro-cap space. One might outperform by 0.05% one year and lag by the same amount the next. Chasing these tiny tracking differences wastes energy; the real driver of wealth is your savings rate and consistency, not the micro-details of CRSP versus Dow Jones index methodologies.
Tax placement mistakes also hurt long-term returns. If you hold taxable accounts alongside tax-advantaged accounts like a Roth IRA, keep your total market index funds in your taxable account for maximum tax efficiency, reserving higher-turnover assets for tax-sheltered spaces.
Frequently Asked Questions
Can I buy VTSAX inside a Fidelity account?
Yes, but Fidelity charges a non-systematic transaction fee for purchasing external mutual funds like VTSAX. To avoid these extra fees, buy FSKAX if you're using mutual funds, or purchase the ETF equivalent, VTI, which trades commission-free across almost all major brokerages including Fidelity.
Is FSKAX better than VTSAX?
Neither fund is universally better. They perform almost identically because they both hold the entire U.S. stock market. FSKAX wins on its zero-dollar minimum investment and slightly lower expense ratio of 0.015%, while VTSAX benefits from Vanguard's unique mutual fund-to-ETF tax structure. Your choice should depend entirely on where your brokerage account lives.
Do I need to buy international stocks alongside FSKAX?
FSKAX covers only the U.S. stock market. While U.S. multinational companies generate substantial revenue overseas, many financial advisors recommend adding an international index fund—such as FTIHX inside Fidelity—to achieve true global diversification. A standard allocation might pair 70% to 80% U.S. total market with 20% to 30% international stock funds.
What is the minimum investment for FSKAX?
Fidelity sets the minimum initial investment for FSKAX at $0. You can buy fractional shares starting with as little as one dollar, making it exceptionally friendly for automated recurring investments. You can review current fund specifications directly on the Fidelity Investments platform.
