SPIIX vs. FXAIX

Last updated Jun 23, 2026

SPIIX (SEI S&P 500 Index Fund Class I) and FXAIX (Fidelity 500 Index Fund) are both mutual funds - SPIIX is a Large Cap Blend Equities fund tracking the S&P 500 Index, while FXAIX is a S&P 500 fund tracking the S&P 500 Index. Both are passively managed. Over the past 10 years, SPIIX returned 14.81%/yr vs 15.58%/yr for FXAIX. With a 1.00 correlation, they move nearly in lockstep. SPIIX charges 0.65%/yr vs 0.02%/yr for FXAIX.

Performance

SPIIX vs. FXAIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in SEI S&P 500 Index Fund Class I (SPIIX) and Fidelity 500 Index Fund (FXAIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with SPIIX having a 9.79% return and FXAIX slightly higher at 10.19%. Over the past 10 years, SPIIX has underperformed FXAIX with an annualized return of 14.81%, while FXAIX has yielded a comparatively higher 15.58% annualized return.

SPIIX

• 1D: 1.09%
• 1M: 0.42%
• YTD: 9.79%
• 6M: 9.27%
• 1Y: 26.18%
• 3Y*: 20.11%
• 5Y*: 13.28%
• 10Y*: 14.81%

FXAIX

• 1D: 1.09%
• 1M: 0.47%
• YTD: 10.19%
• 6M: 9.68%
• 1Y: 27.18%
• 3Y*: 20.98%
• 5Y*: 14.10%
• 10Y*: 15.58%

*Multi-year figures are annualized to reflect compound growth (CAGR)

SPIIX vs. FXAIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SPIIX SEI S&P 500 Index Fund Class I	9.79%	16.97%	24.11%	25.49%	-18.84%	28.04%	17.66%	30.72%	-5.00%	21.06%
FXAIX Fidelity 500 Index Fund	10.19%	17.84%	25.01%	26.29%	-18.14%	28.71%	18.42%	31.48%	-4.43%	21.82%

Correlation

The correlation between SPIIX and FXAIX is 0.99 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.99
Correlation (3Y) Calculated over the trailing 3-year period	0.98
Correlation (5Y) Calculated over the trailing 5-year period	0.99
Correlation (10Y) Calculated over the trailing 10-year period	0.99
Correlation (All Time) Calculated using the full available price history since May 4, 2011	1.00

The correlation between SPIIX and FXAIX has been stable across timeframes, ranging from 0.98 to 1.00 - a consistent structural relationship.

Return for Risk

SPIIX vs. FXAIX — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

SPIIX

SPIIX Risk / Return Rank: 61
SPIIX Sharpe Ratio Rank: 60
SPIIX Sortino Ratio Rank: 54
SPIIX Omega Ratio Rank: 57
SPIIX Calmar Ratio Rank: 62
SPIIX Martin Ratio Rank: 73

FXAIX

FXAIX Risk / Return Rank: 66
FXAIX Sharpe Ratio Rank: 64
FXAIX Sortino Ratio Rank: 59
FXAIX Omega Ratio Rank: 61
FXAIX Calmar Ratio Rank: 68
FXAIX Martin Ratio Rank: 79

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

SPIIX vs. FXAIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for SEI S&P 500 Index Fund Class I (SPIIX) and Fidelity 500 Index Fund (FXAIX). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	SPIIX	FXAIX	Difference
Sharpe ratio: Return per unit of total volatility	2.10	2.17	-0.07
Sortino ratio: Return per unit of downside risk	2.83	2.93	-0.10
Omega ratio: Gain probability vs. loss probability	1.38	1.39	-0.01
Calmar ratio: Return relative to maximum drawdown	2.90	3.04	-0.14
Martin ratio: Return relative to average drawdown	12.99	13.75	-0.76

SPIIX vs. FXAIX - Sharpe Ratio Comparison

The current SPIIX Sharpe Ratio is 2.10, which is comparable to the FXAIX Sharpe Ratio of 2.17. The chart below compares the historical Sharpe Ratios of SPIIX and FXAIX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

SPIIX vs. FXAIX - Drawdown Comparison

The maximum SPIIX drawdown since its inception was -55.78%, which is greater than FXAIX's maximum drawdown of -33.79%. Use the drawdown chart below to compare losses from any high point for SPIIX and FXAIX.

Drawdown Indicators

	SPIIX	FXAIX	Difference
Max Drawdown Largest peak-to-trough decline	-55.78%	-33.79%	-21.99%
Max Drawdown (1Y) Largest decline over 1 year	-9.02%	-8.89%	-0.13%
Max Drawdown (3Y) Largest decline over 3 years	-25.70%	-18.76%	-6.94%
Max Drawdown (5Y) Largest decline over 5 years	-25.70%	-24.50%	-1.20%
Max Drawdown (10Y) Largest decline over 10 years	-33.85%	-33.79%	-0.06%
Current Drawdown Current decline from peak	-1.38%	-1.36%	-0.02%
Average Drawdown Average peak-to-trough decline	-7.27%	-3.79%	-3.48%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.00%	1.96%	+0.04%

Volatility

SPIIX vs. FXAIX - Volatility Comparison

SEI S&P 500 Index Fund Class I (SPIIX) and Fidelity 500 Index Fund (FXAIX) have volatilities of 4.76% and 4.77%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SPIIX	FXAIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.76%	4.77%	-0.01%
Volatility (6M) Calculated over the trailing 6-month period	9.88%	9.91%	-0.03%
Volatility (1Y) Calculated over the trailing 1-year period	12.47%	12.47%	0.00%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.53%	17.01%	+1.52%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.91%	18.11%	+0.80%

SPIIX vs. FXAIX - Expense Ratio Comparison

SPIIX has a 0.65% expense ratio, which is higher than FXAIX's 0.02% expense ratio.

Dividends

SPIIX vs. FXAIX - Dividend Comparison

SPIIX's dividend yield for the trailing twelve months is around 7.67%, more than FXAIX's 1.04% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FXAIX Fidelity 500 Index Fund	1.04%	1.11%	1.25%	1.45%	1.69%	1.22%	1.60%	2.06%	2.72%	1.97%	2.52%	2.83%
SPIIX SEI S&P 500 Index Fund Class I	7.67%	8.42%	12.20%	4.10%	10.27%	7.03%	5.78%	4.04%	3.90%	2.08%	4.34%	1.53%

Frequently Asked Questions

Can I hold both SPIIX and FXAIX in my portfolio?

With a correlation of 0.99, SPIIX and FXAIX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, SPIIX or FXAIX?

FXAIX has higher volatility (4.77%) compared to SPIIX (4.76%). In terms of maximum drawdown, SPIIX dropped -55.78% vs FXAIX's -33.79%.

Which has better risk-adjusted returns?

FXAIX currently has the higher Sharpe Ratio (2.17 vs 2.10), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.