MID vs. IWM

Last updated Jun 24, 2026

MID (American Century Mid Cap Growth Impact ETF) and IWM (iShares Russell 2000 ETF) are both exchange-traded funds - MID is a Mid Cap Growth Equities fund actively managed by American Century, while IWM is a Small Cap Blend Equities fund tracking the Russell 2000 Index. MID is actively managed, while IWM is passively managed. Over the past 5 years, MID returned 3.85%/yr vs 6.27%/yr for IWM. A 0.80 correlation means they provide meaningful diversification when combined. MID charges 0.45%/yr vs 0.19%/yr for IWM.

Performance

MID vs. IWM - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Mid Cap Growth Impact ETF (MID) and iShares Russell 2000 ETF (IWM). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MID achieves a 2.25% return, which is significantly lower than IWM's 20.47% return.

MID

• 1D: -1.39%
• 1M: 1.69%
• YTD: 2.25%
• 6M: 0.73%
• 1Y: 4.00%
• 3Y*: 13.39%
• 5Y*: 3.85%
• 10Y*: —

IWM

• 1D: -0.96%
• 1M: 3.82%
• YTD: 20.47%
• 6M: 17.64%
• 1Y: 40.90%
• 3Y*: 19.22%
• 5Y*: 6.27%
• 10Y*: 11.58%

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

MID vs. IWM - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020
MID American Century Mid Cap Growth Impact ETF	2.25%	8.22%	19.40%	22.20%	-27.44%	10.39%	30.35%
IWM iShares Russell 2000 ETF	20.47%	12.66%	11.38%	16.83%	-20.48%	14.54%	39.20%

Correlation

The correlation between MID and IWM is 0.81, 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	0.81
Correlation (3Y) Calculated over the trailing 3-year period	0.82
Correlation (5Y) Calculated over the trailing 5-year period	0.84
Correlation (All Time) Calculated using the full available price history since Jul 15, 2020	0.80

The correlation between MID and IWM has been stable across timeframes, ranging from 0.80 to 0.84 - a consistent structural relationship.

MID vs. IWM - Sectors Allocation Comparison

Sectors	MID	IWM
Industrials	25.5%	17.3%
Technology	21.9%	20.1%
Healthcare	18.7%	15.6%
Consumer Cyclical	12.2%	8.0%
Energy	7.3%	6.0%
Financial Services	6.1%	15.5%
Utilities	4.4%	3.1%
Basic Materials	2.3%	4.5%
Consumer Defensive	1.6%	2.0%
Communication Services	-	1.7%
Real Estate	-	5.5%

Return for Risk

MID vs. IWM — Risk / Return Rank

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

MID

MID Risk / Return Rank: 12
MID Sharpe Ratio Rank: 12
MID Sortino Ratio Rank: 11
MID Omega Ratio Rank: 11
MID Calmar Ratio Rank: 12
MID Martin Ratio Rank: 13

IWM

IWM Risk / Return Rank: 67
IWM Sharpe Ratio Rank: 66
IWM Sortino Ratio Rank: 64
IWM Omega Ratio Rank: 57
IWM Calmar Ratio Rank: 75
IWM Martin Ratio Rank: 73

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.

MID vs. IWM - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Mid Cap Growth Impact ETF (MID) and iShares Russell 2000 ETF (IWM). 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.

	MID	IWM	Difference
Sharpe ratio: Return per unit of total volatility	0.23	2.08	-1.85
Sortino ratio: Return per unit of downside risk	0.44	2.86	-2.42
Omega ratio: Gain probability vs. loss probability	1.05	1.34	-0.29
Calmar ratio: Return relative to maximum drawdown	0.29	3.73	-3.44
Martin ratio: Return relative to average drawdown	0.85	13.18	-12.33

MID vs. IWM - Sharpe Ratio Comparison

The current MID Sharpe Ratio is 0.23, which is lower than the IWM Sharpe Ratio of 2.08. The chart below compares the historical Sharpe Ratios of MID and IWM, 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

MID vs. IWM - Drawdown Comparison

The maximum MID drawdown since its inception was -40.15%, smaller than the maximum IWM drawdown of -59.05%. Use the drawdown chart below to compare losses from any high point for MID and IWM.

Drawdown Indicators

	MID	IWM	Difference
Max Drawdown Largest peak-to-trough decline	-40.15%	-59.05%	+18.90%
Max Drawdown (1Y) Largest decline over 1 year	-13.89%	-11.03%	-2.86%
Max Drawdown (3Y) Largest decline over 3 years	-23.92%	-27.50%	+3.58%
Max Drawdown (5Y) Largest decline over 5 years	-40.15%	-31.91%	-8.24%
Max Drawdown (10Y) Largest decline over 10 years	—	-41.13%	—
Current Drawdown Current decline from peak	-3.74%	-0.96%	-2.78%
Average Drawdown Average peak-to-trough decline	-13.34%	-10.75%	-2.59%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.73%	3.11%	+1.62%

Volatility

MID vs. IWM - Volatility Comparison

American Century Mid Cap Growth Impact ETF (MID) and iShares Russell 2000 ETF (IWM) have volatilities of 6.68% and 6.56%, 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

	MID	IWM	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.68%	6.56%	+0.12%
Volatility (6M) Calculated over the trailing 6-month period	13.88%	14.31%	-0.43%
Volatility (1Y) Calculated over the trailing 1-year period	17.45%	19.74%	-2.29%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	23.72%	22.61%	+1.11%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.93%	23.06%	+0.87%

MID vs. IWM - Expense Ratio Comparison

MID has a 0.45% expense ratio, which is higher than IWM's 0.19% expense ratio.

Dividends

MID vs. IWM - Dividend Comparison

MID's dividend yield for the trailing twelve months is around 0.18%, less than IWM's 0.90% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
IWM iShares Russell 2000 ETF	0.90%	1.04%	1.15%	1.35%	1.48%	0.94%	1.04%	1.26%	1.40%	1.26%	1.38%	1.54%
MID American Century Mid Cap Growth Impact ETF	0.18%	0.18%	0.17%	0.02%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both MID and IWM in my portfolio?

MID and IWM have a correlation of 0.81, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MID or IWM?

MID has higher volatility (6.68%) compared to IWM (6.56%). In terms of maximum drawdown, MID dropped -40.15% vs IWM's -59.05%.

Which ETF is better, MID or IWM?

On 5-year performance, IWM leads with 6.27% vs 3.85% for MID. On fees, IWM is cheaper at 0.19% per year. On volatility, IWM has been the lower-risk option at 6.56%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, MID or IWM?

Over the 5-year period, IWM has performed better with a 6.27% return vs 3.85%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, MID or IWM?

IWM is cheaper with a 0.19% expense ratio, compared with 0.45% for MID.

Which ETF pays a higher dividend yield, MID or IWM?

IWM has the higher dividend yield at 0.90%, compared with 0.18% for MID.

What is the main difference between MID and IWM?

MID is categorized as Mid Cap Growth Equities, while IWM is Small Cap Blend Equities. They also come from different issuers: American Century and iShares. Their fees differ too: 0.45% for MID and 0.19% for IWM.

Which has better risk-adjusted returns?

IWM currently has the higher Sharpe Ratio (2.08 vs 0.23), 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.