FLAPX vs. FDFIX

Last updated Apr 1, 2026

Compare and contrast key facts about Fidelity Flex Mid Cap Index Fund (FLAPX) and Fidelity Flex 500 Index Fund (FDFIX).

FLAPX is managed by Fidelity. It was launched on Mar 9, 2017. FDFIX is managed by Fidelity. It was launched on Mar 9, 2017.

Performance

FLAPX vs. FDFIX - Performance Comparison

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

FLAPX vs. FDFIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FLAPX Fidelity Flex Mid Cap Index Fund	-0.79%	14.33%	15.30%	17.28%	-17.28%	22.59%	17.30%	30.56%	-9.10%	14.01%
FDFIX Fidelity Flex 500 Index Fund	-7.27%	17.59%	25.06%	26.27%	-18.10%	28.69%	18.46%	31.47%	-4.45%	14.41%

Returns By Period

In the year-to-date period, FLAPX achieves a -0.79% return, which is significantly higher than FDFIX's -7.27% return.

FLAPX

• 1D: -1.02%
• 1M: -8.39%
• YTD: -0.79%
• 6M: 1.43%
• 1Y: 17.43%
• 3Y*: 13.78%
• 5Y*: 7.53%
• 10Y*: —

FDFIX

• 1D: -0.33%
• 1M: -7.59%
• YTD: -7.27%
• 6M: -4.96%
• 1Y: 13.90%
• 3Y*: 17.02%
• 5Y*: 11.31%
• 10Y*: —

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

FLAPX vs. FDFIX - Expense Ratio Comparison

FLAPX has a 0.00% expense ratio, which is lower than FDFIX's 0.00% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

FLAPX

Fidelity Flex Mid Cap Index Fund

FDFIX

Fidelity Flex 500 Index Fund

Return for Risk

FLAPX vs. FDFIX — Risk / Return Rank

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

FLAPX

FLAPX Risk / Return Rank: 48
FLAPX Sharpe Ratio Rank: 46
FLAPX Sortino Ratio Rank: 49
FLAPX Omega Ratio Rank: 45
FLAPX Calmar Ratio Rank: 46
FLAPX Martin Ratio Rank: 52

FDFIX

FDFIX Risk / Return Rank: 42
FDFIX Sharpe Ratio Rank: 39
FDFIX Sortino Ratio Rank: 43
FDFIX Omega Ratio Rank: 47
FDFIX Calmar Ratio Rank: 36
FDFIX Martin Ratio Rank: 46

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.

FLAPX vs. FDFIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Flex Mid Cap Index Fund (FLAPX) and Fidelity Flex 500 Index Fund (FDFIX). 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.

	FLAPX	FDFIX	Difference
Sharpe ratio Return per unit of total volatility	0.90	0.81	+0.09
Sortino ratio Return per unit of downside risk	1.37	1.26	+0.11
Omega ratio Gain probability vs. loss probability	1.19	1.19	0.00
Calmar ratio Return relative to maximum drawdown	1.13	0.96	+0.18
Martin ratio Return relative to average drawdown	5.07	4.59	+0.48
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

FLAPX vs. FDFIX - Sharpe Ratio Comparison

The current FLAPX Sharpe Ratio is 0.90, which is comparable to the FDFIX Sharpe Ratio of 0.81. The chart below compares the historical Sharpe Ratios of FLAPX and FDFIX, 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

	FLAPX	FDFIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.90	0.81	+0.09
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.41	0.67	-0.26
Sharpe Ratio (All Time) Calculated using the full available price history	0.53	0.71	-0.19

Correlation

The correlation between FLAPX and FDFIX is 0.90, 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

FLAPX vs. FDFIX - Dividend Comparison

FLAPX has not paid dividends to shareholders, while FDFIX's dividend yield for the trailing twelve months is around 1.20%.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017
FLAPX Fidelity Flex Mid Cap Index Fund	0.00%	0.00%	1.08%	1.99%	1.82%	2.83%	2.16%	2.18%	2.24%	0.44%
FDFIX Fidelity Flex 500 Index Fund	1.20%	1.11%	1.26%	1.48%	1.70%	1.27%	1.52%	1.78%	2.16%	0.50%

Drawdowns

FLAPX vs. FDFIX - Drawdown Comparison

The maximum FLAPX drawdown since its inception was -40.31%, which is greater than FDFIX's maximum drawdown of -33.77%. Use the drawdown chart below to compare losses from any high point for FLAPX and FDFIX.

Drawdown Indicators

	FLAPX	FDFIX	Difference
Max Drawdown Largest peak-to-trough decline	-40.31%	-33.77%	-6.54%
Max Drawdown (1Y) Largest decline over 1 year	-13.40%	-12.13%	-1.27%
Max Drawdown (5Y) Largest decline over 5 years	-26.09%	-24.51%	-1.58%
Current Drawdown Current decline from peak	-9.21%	-8.99%	-0.22%
Average Drawdown Average peak-to-trough decline	-6.21%	-4.64%	-1.57%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.00%	2.60%	+0.40%

Volatility

FLAPX vs. FDFIX - Volatility Comparison

Fidelity Flex Mid Cap Index Fund (FLAPX) has a higher volatility of 6.04% compared to Fidelity Flex 500 Index Fund (FDFIX) at 4.22%. This indicates that FLAPX's price experiences larger fluctuations and is considered to be riskier than FDFIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FLAPX	FDFIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.04%	4.22%	+1.82%
Volatility (6M) Calculated over the trailing 6-month period	11.93%	9.16%	+2.77%
Volatility (1Y) Calculated over the trailing 1-year period	20.19%	18.20%	+1.99%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.49%	16.91%	+1.58%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.02%	18.68%	+1.34%