FNKFX vs. FMDGX

Last updated Jun 24, 2026

FNKFX (Fidelity Mid-Cap Stock K6 Fund) and FMDGX (Fidelity Mid Cap Growth Index Fund) are both mutual funds - FNKFX is a Mid Cap Blend Equities fund managed by Fidelity, while FMDGX is a Mid Cap Growth Equities fund tracking the Russell Midcap Growth Index. Over the past 5 years, FNKFX returned 12.64%/yr vs 5.63%/yr for FMDGX. A 0.79 correlation means they provide meaningful diversification when combined. FNKFX charges 0.52%/yr vs 0.05%/yr for FMDGX.

Performance

FNKFX vs. FMDGX - Performance Comparison

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

Returns By Period

In the year-to-date period, FNKFX achieves a 18.97% return, which is significantly higher than FMDGX's 3.82% return.

FNKFX

• 1D: 0.71%
• 1M: 3.87%
• YTD: 18.97%
• 6M: 16.69%
• 1Y: 31.22%
• 3Y*: 21.19%
• 5Y*: 12.64%
• 10Y*: —

FMDGX

• 1D: -0.11%
• 1M: 1.82%
• YTD: 3.82%
• 6M: 1.82%
• 1Y: 5.26%
• 3Y*: 15.69%
• 5Y*: 5.63%
• 10Y*: —

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

FNKFX vs. FMDGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
FNKFX Fidelity Mid-Cap Stock K6 Fund	18.97%	11.07%	21.99%	11.55%	-5.98%	27.16%	11.27%	5.79%
FMDGX Fidelity Mid Cap Growth Index Fund	3.82%	8.60%	22.03%	25.79%	-26.67%	12.67%	34.84%	4.63%

Correlation

The correlation between FNKFX and FMDGX is 0.84, 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	0.84
Correlation (3Y) Calculated over the trailing 3-year period	0.86
Correlation (5Y) Calculated over the trailing 5-year period	0.84
Correlation (All Time) Calculated using the full available price history since Jul 17, 2019	0.79

The correlation between FNKFX and FMDGX has been stable across timeframes, ranging from 0.79 to 0.86 - a consistent structural relationship.

Return for Risk

FNKFX vs. FMDGX — Risk / Return Rank

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

FNKFX

FNKFX Risk / Return Rank: 64
FNKFX Sharpe Ratio Rank: 54
FNKFX Sortino Ratio Rank: 53
FNKFX Omega Ratio Rank: 48
FNKFX Calmar Ratio Rank: 84
FNKFX Martin Ratio Rank: 83

FMDGX

FMDGX Risk / Return Rank: 5
FMDGX Sharpe Ratio Rank: 5
FMDGX Sortino Ratio Rank: 5
FMDGX Omega Ratio Rank: 5
FMDGX Calmar Ratio Rank: 5
FMDGX Martin Ratio Rank: 6

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. FMDGX - Risk-Adjusted Trends Comparison

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

	FNKFX	FMDGX	Difference
Sharpe ratio: Return per unit of total volatility	2.00	0.36	+1.64
Sortino ratio: Return per unit of downside risk	2.80	0.62	+2.17
Omega ratio: Gain probability vs. loss probability	1.35	1.07	+0.28
Calmar ratio: Return relative to maximum drawdown	3.79	0.42	+3.37
Martin ratio: Return relative to average drawdown	14.52	1.20	+13.32

FNKFX vs. FMDGX - Sharpe Ratio Comparison

The current FNKFX Sharpe Ratio is 2.00, which is higher than the FMDGX Sharpe Ratio of 0.36. The chart below compares the historical Sharpe Ratios of FNKFX and FMDGX, 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

FNKFX vs. FMDGX - Drawdown Comparison

The maximum FNKFX drawdown since its inception was -41.25%, which is greater than FMDGX's maximum drawdown of -38.59%. Use the drawdown chart below to compare losses from any high point for FNKFX and FMDGX.

Drawdown Indicators

	FNKFX	FMDGX	Difference
Max Drawdown Largest peak-to-trough decline	-41.25%	-38.59%	-2.66%
Max Drawdown (1Y) Largest decline over 1 year	-8.67%	-14.75%	+6.08%
Max Drawdown (3Y) Largest decline over 3 years	-21.86%	-25.30%	+3.44%
Max Drawdown (5Y) Largest decline over 5 years	-21.86%	-38.59%	+16.73%
Current Drawdown Current decline from peak	0.00%	-2.08%	+2.08%
Average Drawdown Average peak-to-trough decline	-4.95%	-11.14%	+6.19%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.25%	5.09%	-2.84%

Volatility

FNKFX vs. FMDGX - Volatility Comparison

Fidelity Mid-Cap Stock K6 Fund (FNKFX) and Fidelity Mid Cap Growth Index Fund (FMDGX) have volatilities of 5.52% and 5.70%, 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

	FNKFX	FMDGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.52%	5.70%	-0.18%
Volatility (6M) Calculated over the trailing 6-month period	13.06%	13.38%	-0.32%
Volatility (1Y) Calculated over the trailing 1-year period	16.47%	17.07%	-0.60%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.90%	22.45%	-3.55%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.96%	24.30%	-2.34%

FNKFX vs. FMDGX - Expense Ratio Comparison

FNKFX has a 0.52% expense ratio, which is higher than FMDGX's 0.05% expense ratio.

Dividends

FNKFX vs. FMDGX - Dividend Comparison

FNKFX's dividend yield for the trailing twelve months is around 3.85%, more than FMDGX's 1.79% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019
FMDGX Fidelity Mid Cap Growth Index Fund	1.79%	1.85%	0.47%	0.63%	0.81%	6.43%	0.36%	0.29%
FNKFX Fidelity Mid-Cap Stock K6 Fund	3.85%	0.59%	12.35%	0.99%	2.91%	4.03%	1.45%	0.52%

Frequently Asked Questions

Can I hold both FNKFX and FMDGX in my portfolio?

FNKFX and FMDGX have a correlation of 0.84, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, FNKFX or FMDGX?

FMDGX has higher volatility (5.70%) compared to FNKFX (5.52%). In terms of maximum drawdown, FNKFX dropped -41.25% vs FMDGX's -38.59%.

Which has better risk-adjusted returns?

FNKFX currently has the higher Sharpe Ratio (2.00 vs 0.36), 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.