ACLAX vs. FDFIX

Last updated Jun 4, 2026

ACLAX (American Century Mid Cap Value Fund A Class) and FDFIX (Fidelity Flex 500 Index Fund) are both mutual funds - ACLAX is a Mid Cap Value Equities fund managed by American Century, while FDFIX is a Large Cap Blend Equities fund managed by Fidelity. Over the past 5 years, ACLAX returned 6.59%/yr vs 14.20%/yr for FDFIX. A 0.76 correlation means they provide meaningful diversification when combined. ACLAX charges 1.22%/yr vs 0.00%/yr for FDFIX.

Performance

ACLAX vs. FDFIX - Performance Comparison

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

Returns By Period

In the year-to-date period, ACLAX achieves a 8.06% return, which is significantly lower than FDFIX's 11.53% return.

ACLAX

• 1D: 0.89%
• 1M: 2.18%
• YTD: 8.06%
• 6M: 7.73%
• 1Y: 15.86%
• 3Y*: 10.71%
• 5Y*: 6.59%
• 10Y*: 8.64%

FDFIX

• 1D: 0.22%
• 1M: 6.02%
• YTD: 11.53%
• 6M: 11.45%
• 1Y: 28.49%
• 3Y*: 22.62%
• 5Y*: 14.20%
• 10Y*: —

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

ACLAX vs. FDFIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
ACLAX American Century Mid Cap Value Fund A Class	8.06%	8.52%	8.18%	5.93%	-1.53%	23.01%	1.44%	28.55%	-12.93%	8.35%
FDFIX Fidelity Flex 500 Index Fund	11.53%	17.59%	25.06%	26.27%	-18.10%	28.69%	18.46%	31.47%	-4.45%	14.41%

Correlation

The correlation between ACLAX and FDFIX is 0.54, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.54
Correlation (3Y) Calculated over the trailing 3-year period	0.59
Correlation (5Y) Calculated over the trailing 5-year period	0.72
Correlation (All Time) Calculated using the full available price history since Mar 10, 2017	0.76

Over the past year, the correlation between ACLAX and FDFIX has dropped to 0.54 - well below their long-term average of 0.76, suggesting their price drivers have been diverging.

Return for Risk

ACLAX vs. FDFIX — Risk / Return Rank

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

ACLAX

ACLAX Risk / Return Rank: 25
ACLAX Sharpe Ratio Rank: 24
ACLAX Sortino Ratio Rank: 26
ACLAX Omega Ratio Rank: 22
ACLAX Calmar Ratio Rank: 28
ACLAX Martin Ratio Rank: 26

FDFIX

FDFIX Risk / Return Rank: 70
FDFIX Sharpe Ratio Rank: 72
FDFIX Sortino Ratio Rank: 64
FDFIX Omega Ratio Rank: 64
FDFIX Calmar Ratio Rank: 72
FDFIX Martin Ratio Rank: 80

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.

ACLAX vs. FDFIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Mid Cap Value Fund A Class (ACLAX) 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.

	ACLAX	FDFIX	Difference
Sharpe ratio: Return per unit of total volatility	1.40	2.47	-1.07
Sortino ratio: Return per unit of downside risk	2.14	3.34	-1.21
Omega ratio: Gain probability vs. loss probability	1.25	1.45	-0.20
Calmar ratio: Return relative to maximum drawdown	1.95	3.28	-1.33
Martin ratio: Return relative to average drawdown	6.25	14.96	-8.71
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

ACLAX vs. FDFIX - Sharpe Ratio Comparison

The current ACLAX Sharpe Ratio is 1.40, which is lower than the FDFIX Sharpe Ratio of 2.47. The chart below compares the historical Sharpe Ratios of ACLAX and FDFIX, 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

	ACLAX	FDFIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.40	2.47	-1.07
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.45	0.84	-0.39
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.50	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.49	0.82	-0.34

Drawdowns

ACLAX vs. FDFIX - Drawdown Comparison

The maximum ACLAX drawdown since its inception was -51.37%, which is greater than FDFIX's maximum drawdown of -33.77%. Use the drawdown chart below to compare losses from any high point for ACLAX and FDFIX.

Drawdown Indicators

	ACLAX	FDFIX	Difference
Max Drawdown Largest peak-to-trough decline	-51.37%	-33.77%	-17.60%
Max Drawdown (1Y) Largest decline over 1 year	-8.50%	-8.99%	+0.49%
Max Drawdown (3Y) Largest decline over 3 years	-14.67%	-18.76%	+4.09%
Max Drawdown (5Y) Largest decline over 5 years	-17.55%	-24.51%	+6.96%
Max Drawdown (10Y) Largest decline over 10 years	-39.24%	—	—
Current Drawdown Current decline from peak	-1.51%	0.00%	-1.51%
Average Drawdown Average peak-to-trough decline	-6.26%	-4.58%	-1.68%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.65%	1.97%	+0.68%

Volatility

ACLAX vs. FDFIX - Volatility Comparison

American Century Mid Cap Value Fund A Class (ACLAX) and Fidelity Flex 500 Index Fund (FDFIX) have volatilities of 3.02% and 2.92%, 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

	ACLAX	FDFIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.02%	2.92%	+0.10%
Volatility (6M) Calculated over the trailing 6-month period	8.48%	9.03%	-0.55%
Volatility (1Y) Calculated over the trailing 1-year period	11.88%	11.96%	-0.08%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	14.65%	16.95%	-2.30%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.48%	18.59%	-1.11%

ACLAX vs. FDFIX - Expense Ratio Comparison

ACLAX has a 1.22% expense ratio, which is higher than FDFIX's 0.00% expense ratio.

Dividends

ACLAX vs. FDFIX - Dividend Comparison

ACLAX's dividend yield for the trailing twelve months is around 13.11%, more than FDFIX's 1.03% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ACLAX American Century Mid Cap Value Fund A Class	13.11%	14.24%	8.53%	5.01%	14.77%	15.72%	1.62%	1.23%	14.17%	9.25%	3.82%	10.86%
FDFIX Fidelity Flex 500 Index Fund	1.03%	1.11%	1.26%	1.48%	1.70%	1.27%	1.52%	1.78%	2.16%	0.50%	0.00%	0.00%

Frequently Asked Questions

Can I hold both ACLAX and FDFIX in my portfolio?

ACLAX and FDFIX have a correlation of 0.54, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, ACLAX or FDFIX?

ACLAX has higher volatility (3.02%) compared to FDFIX (2.92%). In terms of maximum drawdown, ACLAX dropped -51.37% vs FDFIX's -33.77%.

Which has better risk-adjusted returns?

FDFIX currently has the higher Sharpe Ratio (2.47 vs 1.40), 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.