FNKFX vs. FXAIX

Last updated Apr 1, 2026

Compare and contrast key facts about Fidelity Mid-Cap Stock K6 Fund (FNKFX) and Fidelity 500 Index Fund (FXAIX).

FNKFX is managed by Fidelity. It was launched on Jun 13, 2019. FXAIX is a passively managed fund by Fidelity that tracks the performance of the S&P 500 Index. It was launched on Feb 17, 1988.

Performance

FNKFX vs. FXAIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity Mid-Cap Stock K6 Fund (FNKFX) and Fidelity 500 Index Fund (FXAIX). The values are adjusted to include any dividend payments, if applicable.

FNKFX vs. FXAIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
FNKFX Fidelity Mid-Cap Stock K6 Fund	1.09%	11.07%	21.99%	11.55%	-5.98%	27.16%	11.27%	8.97%
FXAIX Fidelity 500 Index Fund	-7.05%	17.84%	25.01%	26.29%	-18.14%	28.71%	18.42%	12.90%

Returns By Period

In the year-to-date period, FNKFX achieves a 1.09% return, which is significantly higher than FXAIX's -7.05% return.

FNKFX

• 1D: -1.40%
• 1M: -7.76%
• YTD: 1.09%
• 6M: 3.47%
• 1Y: 19.33%
• 3Y*: 14.58%
• 5Y*: 9.94%
• 10Y*: —

FXAIX

• 1D: -0.39%
• 1M: -7.68%
• YTD: -7.05%
• 6M: -4.59%
• 1Y: 14.42%
• 3Y*: 17.17%
• 5Y*: 11.40%
• 10Y*: 13.75%

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

FNKFX vs. FXAIX - Expense Ratio Comparison

FNKFX has a 0.52% expense ratio, which is higher than FXAIX's 0.02% expense ratio.

FNKFX

Fidelity Mid-Cap Stock K6 Fund

FXAIX

Fidelity 500 Index Fund

Return for Risk

FNKFX vs. FXAIX — Risk / Return Rank

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

FNKFX

FNKFX Risk / Return Rank: 53
FNKFX Sharpe Ratio Rank: 51
FNKFX Sortino Ratio Rank: 54
FNKFX Omega Ratio Rank: 50
FNKFX Calmar Ratio Rank: 51
FNKFX Martin Ratio Rank: 59

FXAIX

FXAIX Risk / Return Rank: 46
FXAIX Sharpe Ratio Rank: 41
FXAIX Sortino Ratio Rank: 45
FXAIX Omega Ratio Rank: 50
FXAIX Calmar Ratio Rank: 41
FXAIX Martin Ratio Rank: 53

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.

FNKFX vs. FXAIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Mid-Cap Stock K6 Fund (FNKFX) 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.

	FNKFX	FXAIX	Difference
Sharpe ratio Return per unit of total volatility	0.98	0.84	+0.14
Sortino ratio Return per unit of downside risk	1.47	1.30	+0.17
Omega ratio Gain probability vs. loss probability	1.20	1.20	+0.01
Calmar ratio Return relative to maximum drawdown	1.24	1.05	+0.19
Martin ratio Return relative to average drawdown	5.64	5.13	+0.51
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

FNKFX vs. FXAIX - Sharpe Ratio Comparison

The current FNKFX Sharpe Ratio is 0.98, which is comparable to the FXAIX Sharpe Ratio of 0.84. The chart below compares the historical Sharpe Ratios of FNKFX and FXAIX, offering insights into how both investments have performed under varying market conditions. These values are calculated using daily returns over the previous 12 months.

Sharpe Ratios by Period

	FNKFX	FXAIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.98	0.84	+0.14
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.53	0.68	-0.15
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.77	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.57	0.75	-0.19

Correlation

The correlation between FNKFX and FXAIX is 0.83, which is considered to be high. That indicates a strong positive relationship between their price movements. Having highly-correlated positions in a portfolio may signal a lack of diversification, potentially leading to increased risk during market downturns.

Dividends

FNKFX vs. FXAIX - Dividend Comparison

FNKFX's dividend yield for the trailing twelve months is around 0.58%, less than FXAIX's 1.20% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FNKFX Fidelity Mid-Cap Stock K6 Fund	0.58%	0.59%	12.35%	0.99%	2.91%	4.03%	1.45%	0.52%	0.00%	0.00%	0.00%	0.00%
FXAIX Fidelity 500 Index Fund	1.20%	1.11%	1.25%	1.45%	1.69%	1.22%	1.60%	2.06%	2.72%	1.97%	2.52%	2.83%

Drawdowns

FNKFX vs. FXAIX - Drawdown Comparison

The maximum FNKFX drawdown since its inception was -41.25%, which is greater than FXAIX's maximum drawdown of -33.79%. Use the drawdown chart below to compare losses from any high point for FNKFX and FXAIX.

Drawdown Indicators

	FNKFX	FXAIX	Difference
Max Drawdown Largest peak-to-trough decline	-41.25%	-33.79%	-7.46%
Max Drawdown (1Y) Largest decline over 1 year	-13.51%	-12.13%	-1.38%
Max Drawdown (5Y) Largest decline over 5 years	-21.86%	-24.50%	+2.64%
Max Drawdown (10Y) Largest decline over 10 years	—	-33.79%	—
Current Drawdown Current decline from peak	-8.67%	-8.89%	+0.22%
Average Drawdown Average peak-to-trough decline	-5.07%	-3.83%	-1.24%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.98%	2.50%	+0.48%

Volatility

FNKFX vs. FXAIX - Volatility Comparison

Fidelity Mid-Cap Stock K6 Fund (FNKFX) has a higher volatility of 6.61% compared to Fidelity 500 Index Fund (FXAIX) at 4.24%. This indicates that FNKFX's price experiences larger fluctuations and is considered to be riskier than FXAIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FNKFX	FXAIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.61%	4.24%	+2.37%
Volatility (6M) Calculated over the trailing 6-month period	12.09%	9.08%	+3.01%
Volatility (1Y) Calculated over the trailing 1-year period	20.24%	18.13%	+2.11%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.73%	16.88%	+1.85%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.06%	18.03%	+4.03%