FNKFX vs. FSMAX

Last updated Jun 3, 2026

FNKFX (Fidelity Mid-Cap Stock K6 Fund) and FSMAX (Fidelity Extended Market Index Fund) are both mutual funds - FNKFX is a Mid Cap Blend Equities fund managed by Fidelity, while FSMAX is a Mid Cap Growth Equities fund managed by Fidelity. Over the past 5 years, FNKFX returned 11.28%/yr vs 6.47%/yr for FSMAX. Their correlation of 0.90 suggests significant overlap in exposure. FNKFX charges 0.52%/yr vs 0.04%/yr for FSMAX.

Performance

FNKFX vs. FSMAX - Performance Comparison

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

Returns By Period

In the year-to-date period, FNKFX achieves a 15.40% return, which is significantly higher than FSMAX's 13.67% return.

FNKFX

• 1D: -0.35%
• 1M: 1.88%
• YTD: 15.40%
• 6M: 16.75%
• 1Y: 29.58%
• 3Y*: 20.10%
• 5Y*: 11.28%
• 10Y*: —

FSMAX

• 1D: 0.26%
• 1M: 4.31%
• YTD: 13.67%
• 6M: 13.96%
• 1Y: 30.51%
• 3Y*: 19.71%
• 5Y*: 6.47%
• 10Y*: 12.05%

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

FNKFX vs. FSMAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
FNKFX Fidelity Mid-Cap Stock K6 Fund	15.40%	11.07%	21.99%	11.55%	-5.98%	27.16%	11.27%	8.97%
FSMAX Fidelity Extended Market Index Fund	13.67%	11.40%	16.99%	25.36%	-26.44%	12.41%	32.28%	9.04%

Correlation

The correlation between FNKFX and FSMAX is 0.92, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.92
Correlation (3Y) Calculated over the trailing 3-year period	0.93
Correlation (5Y) Calculated over the trailing 5-year period	0.91
Correlation (All Time) Calculated using the full available price history since Jun 14, 2019	0.90

The correlation between FNKFX and FSMAX has been stable across timeframes, ranging from 0.90 to 0.93 - a consistent structural relationship.

Return for Risk

FNKFX vs. FSMAX — 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: 41
FNKFX Sortino Ratio Rank: 41
FNKFX Omega Ratio Rank: 39
FNKFX Calmar Ratio Rank: 75
FNKFX Martin Ratio Rank: 69

FSMAX

FSMAX Risk / Return Rank: 43
FSMAX Sharpe Ratio Rank: 38
FSMAX Sortino Ratio Rank: 36
FSMAX Omega Ratio Rank: 34
FSMAX Calmar Ratio Rank: 59
FSMAX Martin Ratio Rank: 51

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. FSMAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Mid-Cap Stock K6 Fund (FNKFX) and Fidelity Extended Market Index Fund (FSMAX). 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	FSMAX	Difference
Sharpe ratio Return per unit of total volatility	1.89	1.80	+0.09
Sortino ratio Return per unit of downside risk	2.69	2.52	+0.17
Omega ratio Gain probability vs. loss probability	1.33	1.31	+0.02
Calmar ratio Return relative to maximum drawdown	3.42	2.97	+0.45
Martin ratio Return relative to average drawdown	13.29	10.52	+2.78
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. FSMAX - Sharpe Ratio Comparison

The current FNKFX Sharpe Ratio is 1.89, which is comparable to the FSMAX Sharpe Ratio of 1.80. The chart below compares the historical Sharpe Ratios of FNKFX and FSMAX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	FNKFX	FSMAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.89	1.80	+0.09
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.60	0.29	+0.31
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.40	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.65	0.46	+0.19

Drawdowns

FNKFX vs. FSMAX - Drawdown Comparison

The maximum FNKFX drawdown since its inception was -41.25%, smaller than the maximum FSMAX drawdown of -50.55%. Use the drawdown chart below to compare losses from any high point for FNKFX and FSMAX.

Drawdown Indicators

	FNKFX	FSMAX	Difference
Max Drawdown Largest peak-to-trough decline	-41.25%	-50.55%	+9.30%
Max Drawdown (1Y) Largest decline over 1 year	-8.67%	-10.26%	+1.59%
Max Drawdown (3Y) Largest decline over 3 years	-21.86%	-26.82%	+4.96%
Max Drawdown (5Y) Largest decline over 5 years	-21.86%	-36.31%	+14.45%
Max Drawdown (10Y) Largest decline over 10 years	—	-50.55%	—
Current Drawdown Current decline from peak	-1.33%	0.00%	-1.33%
Average Drawdown Average peak-to-trough decline	-4.98%	-12.17%	+7.19%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.23%	2.90%	-0.67%

Volatility

FNKFX vs. FSMAX - Volatility Comparison

Fidelity Mid-Cap Stock K6 Fund (FNKFX) has a higher volatility of 4.90% compared to Fidelity Extended Market Index Fund (FSMAX) at 4.63%. This indicates that FNKFX's price experiences larger fluctuations and is considered to be riskier than FSMAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FNKFX	FSMAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.90%	4.63%	+0.27%
Volatility (6M) Calculated over the trailing 6-month period	12.43%	12.44%	-0.01%
Volatility (1Y) Calculated over the trailing 1-year period	15.82%	17.18%	-1.36%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.85%	22.32%	-3.47%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.97%	30.24%	-8.27%

FNKFX vs. FSMAX - Expense Ratio Comparison

FNKFX has a 0.52% expense ratio, which is higher than FSMAX's 0.04% expense ratio.

Dividends

FNKFX vs. FSMAX - Dividend Comparison

FNKFX's dividend yield for the trailing twelve months is around 0.51%, more than FSMAX's 0.50% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FNKFX Fidelity Mid-Cap Stock K6 Fund	0.51%	0.59%	12.35%	0.99%	2.91%	4.03%	1.45%	0.52%	0.00%	0.00%	0.00%	0.00%
FSMAX Fidelity Extended Market Index Fund	0.50%	0.57%	0.48%	1.17%	1.90%	7.49%	2.14%	4.30%	6.09%	5.44%	4.85%	6.34%

Frequently Asked Questions

Can I hold both FNKFX and FSMAX in my portfolio?

With a correlation of 0.92, FNKFX and FSMAX 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, FNKFX or FSMAX?

FNKFX has higher volatility (4.90%) compared to FSMAX (4.63%). In terms of maximum drawdown, FNKFX dropped -41.25% vs FSMAX's -50.55%.

Which has better risk-adjusted returns?

FNKFX currently has the higher Sharpe Ratio (1.89 vs 1.80), 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.