ACRNX vs. FSMAX

Last updated Jun 4, 2026

ACRNX (Columbia Acorn Fund) and FSMAX (Fidelity Extended Market Index Fund) are both Mid Cap Growth Equities funds. Over the past 10 years, ACRNX returned 9.49%/yr vs 12.17%/yr for FSMAX. With a 0.95 correlation, they move nearly in lockstep. ACRNX charges 0.83%/yr vs 0.04%/yr for FSMAX.

Performance

ACRNX vs. FSMAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Columbia Acorn Fund (ACRNX) and Fidelity Extended Market Index Fund (FSMAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both stocks are quite close, with ACRNX having a 15.48% return and FSMAX slightly lower at 14.89%. Over the past 10 years, ACRNX has underperformed FSMAX with an annualized return of 9.49%, while FSMAX has yielded a comparatively higher 12.17% annualized return.

ACRNX

• 1D: 1.75%
• 1M: 7.60%
• YTD: 15.48%
• 6M: 12.57%
• 1Y: 30.40%
• 3Y*: 14.71%
• 5Y*: 3.94%
• 10Y*: 9.49%

FSMAX

• 1D: 1.07%
• 1M: 5.80%
• YTD: 14.89%
• 6M: 13.61%
• 1Y: 30.08%
• 3Y*: 20.13%
• 5Y*: 6.91%
• 10Y*: 12.17%

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

ACRNX vs. FSMAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
ACRNX Columbia Acorn Fund	15.48%	4.80%	14.46%	21.85%	-33.80%	8.62%	29.65%	26.65%	-8.82%	25.22%
FSMAX Fidelity Extended Market Index Fund	14.89%	11.40%	16.99%	25.36%	-26.44%	12.41%	32.28%	28.01%	-9.44%	18.04%

Correlation

The correlation between ACRNX and FSMAX is 0.94, 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	0.94
Correlation (3Y) Calculated over the trailing 3-year period	0.95
Correlation (5Y) Calculated over the trailing 5-year period	0.95
Correlation (10Y) Calculated over the trailing 10-year period	0.94
Correlation (All Time) Calculated using the full available price history since Sep 9, 2011	0.95

The correlation between ACRNX and FSMAX has been stable across timeframes, ranging from 0.94 to 0.95 - a consistent structural relationship.

Return for Risk

ACRNX vs. FSMAX — Risk / Return Rank

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

ACRNX

ACRNX Risk / Return Rank: 29
ACRNX Sharpe Ratio Rank: 30
ACRNX Sortino Ratio Rank: 28
ACRNX Omega Ratio Rank: 27
ACRNX Calmar Ratio Rank: 27
ACRNX Martin Ratio Rank: 32

FSMAX

FSMAX Risk / Return Rank: 47
FSMAX Sharpe Ratio Rank: 41
FSMAX Sortino Ratio Rank: 39
FSMAX Omega Ratio Rank: 37
FSMAX Calmar Ratio Rank: 66
FSMAX Martin Ratio Rank: 54

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.

ACRNX vs. FSMAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Columbia Acorn Fund (ACRNX) 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.

	ACRNX	FSMAX	Difference
Sharpe ratio: Return per unit of total volatility	1.57	1.87	-0.30
Sortino ratio: Return per unit of downside risk	2.21	2.60	-0.39
Omega ratio: Gain probability vs. loss probability	1.27	1.32	-0.05
Calmar ratio: Return relative to maximum drawdown	1.93	3.12	-1.19
Martin ratio: Return relative to average drawdown	7.37	11.05	-3.68
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

ACRNX vs. FSMAX - Sharpe Ratio Comparison

The current ACRNX Sharpe Ratio is 1.57, which is comparable to the FSMAX Sharpe Ratio of 1.87. The chart below compares the historical Sharpe Ratios of ACRNX 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

	ACRNX	FSMAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.57	1.87	-0.30
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.16	0.31	-0.15
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.41	0.40	+0.01
Sharpe Ratio (All Time) Calculated using the full available price history	0.66	0.46	+0.19

Drawdowns

ACRNX vs. FSMAX - Drawdown Comparison

The maximum ACRNX drawdown since its inception was -56.70%, which is greater than FSMAX's maximum drawdown of -50.55%. Use the drawdown chart below to compare losses from any high point for ACRNX and FSMAX.

Drawdown Indicators

	ACRNX	FSMAX	Difference
Max Drawdown Largest peak-to-trough decline	-56.70%	-50.55%	-6.15%
Max Drawdown (1Y) Largest decline over 1 year	-16.63%	-10.26%	-6.37%
Max Drawdown (3Y) Largest decline over 3 years	-30.05%	-26.82%	-3.23%
Max Drawdown (5Y) Largest decline over 5 years	-45.58%	-36.31%	-9.27%
Max Drawdown (10Y) Largest decline over 10 years	-45.58%	-50.55%	+4.97%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-8.77%	-12.17%	+3.40%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.35%	2.90%	+1.45%

Volatility

ACRNX vs. FSMAX - Volatility Comparison

Columbia Acorn Fund (ACRNX) has a higher volatility of 6.41% compared to Fidelity Extended Market Index Fund (FSMAX) at 4.70%. This indicates that ACRNX'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

	ACRNX	FSMAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.41%	4.70%	+1.71%
Volatility (6M) Calculated over the trailing 6-month period	16.24%	12.46%	+3.78%
Volatility (1Y) Calculated over the trailing 1-year period	20.50%	17.17%	+3.33%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	25.00%	22.33%	+2.67%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.06%	30.24%	-7.18%

ACRNX vs. FSMAX - Expense Ratio Comparison

ACRNX has a 0.83% expense ratio, which is higher than FSMAX's 0.04% expense ratio.

Dividends

ACRNX vs. FSMAX - Dividend Comparison

ACRNX has not paid dividends to shareholders, while FSMAX's dividend yield for the trailing twelve months is around 0.50%.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ACRNX Columbia Acorn Fund	0.00%	0.00%	0.00%	0.00%	5.30%	26.17%	13.28%	11.43%	8.55%	23.63%	39.09%	63.48%
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 ACRNX and FSMAX in my portfolio?

With a correlation of 0.94, ACRNX 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, ACRNX or FSMAX?

ACRNX has higher volatility (6.41%) compared to FSMAX (4.70%). In terms of maximum drawdown, ACRNX dropped -56.70% vs FSMAX's -50.55%.

Which has better risk-adjusted returns?

FSMAX currently has the higher Sharpe Ratio (1.87 vs 1.57), 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.