VOO vs FXAIX: Which is Better?

What is FXAIX?

FXAIX is the Fidelity 500 Index Fund, a mutual fund that tracks the S&P 500. Managed by Fidelity Investments, FXAIX offers exposure to 500 of the largest U.S. companies, making it a core holding for many retirement and brokerage accounts.

• Fund Type: Mutual Fund
• Expense Ratio: 0.015%
• Minimum Investment: $0 (for Fidelity accounts)
• Dividend Yield: ~1.5% (as of mid-2025)
• Assets Under Management (AUM): Over $400 billion

FXAIX is often used in employer-sponsored plans like 401(k)s due to its low cost and accessibility.

What is VOO?

VOO, or the Vanguard S&P 500 ETF, is an exchange-traded fund (ETF) that also tracks the S&P 500. Offered by Vanguard, VOO is structured differently from a mutual fund and is traded on stock exchanges like a regular stock.

• Fund Type: ETF
• Expense Ratio: 0.03%
• Minimum Investment: Price of 1 share (~$480 as of July 2025)
• Dividend Yield: ~1.5%
• AUM: Over $350 billion

VOO is popular among DIY investors and traders for its liquidity and intraday trading flexibility.

Difference Between FXAIX and VOO

While VOO and FXAIX both track the S&P 500, key differences lie in structure, tax treatment, and flexibility. Here’s a side-by-side breakdown:

For long-term passive investors, the cost savings in FXAIX may be slightly more favorable. However, for those needing real-time trades or using a non-Fidelity broker, VOO offers greater flexibility.

VOO vs FXAIX Performance

Both VOO and FXAIX closely mirror the S&P 500’s returns. Over the past 5 years (as of mid-2025), the performance differences are negligible:

• VOO 5-Year Return: ~84%
• FXAIX 5-Year Return: ~85%

These small differences are often due to timing of reinvestments, fund inflows, or slight tracking errors, not structural flaws. For all practical purposes, their returns are nearly identical over long periods.

FXAIX vs VOO: Which Is Better Investment?

When deciding between VOO vs FXAIX, there is no one-size-fits-all answer. Both funds offer low-cost, diversified exposure to the S&P 500, and long-term performance differences are minimal. The better choice depends entirely on the investor’s needs, platform, and strategy.

VOO may be better suited for those who value intra-day trading, tax efficiency, or want to use ETFs in a brokerage account.

FXAIX may be ideal for long-term investors using Fidelity accounts or retirement plans, where simplicity and automatic reinvestment are key.

In terms of historical returns, both funds have tracked the S&P 500 closely, with virtually identical performance over time. Ultimately, the “best” investment comes down to platform preference, tax considerations, and how actively you manage your portfolio.

FXAIX or VOO for Taxable Accounts?

For taxable brokerage accounts, VOO may have an edge due to the ETF structure’s built-in tax efficiency. ETFs like VOO use in-kind redemptions, which help reduce capital gains distributions. Mutual funds like FXAIX are generally less tax efficient, especially when managing large inflows/outflows.

However, in tax-advantaged accounts (e.g., IRAs, 401(k)s), this advantage is neutralized.

Investor Considerations:

Conclusion

Both VOO and FXAIX are excellent S&P 500 index funds. The right choice depends on your investment platform, trading style, and tax situation:

Choose FXAIX if you prefer simplicity, automatic reinvestments, and ultra-low costs within Fidelity.

Choose VOO if you want trading flexibility, use Vanguard or other brokers, or plan to execute options strategies.

Over a 10–20 year horizon, both funds will likely deliver nearly identical returns. But the structure and user preference ultimately determine which is better for your portfolio.

At Ultima Markets, we equip investors and traders with market insights that help optimize their asset selection. Whether you’re building long-term wealth or actively managing a portfolio, understanding product structure is key to maximizing returns.