MID vs. TWHIX

Last updated Jun 25, 2026

MID (American Century Mid Cap Growth Impact ETF) and TWHIX (American Century Heritage Fund) are both Mid Cap Growth Equities funds from American Century. Over the past 5 years, MID returned 3.97%/yr vs 4.31%/yr for TWHIX. With a 0.96 correlation, they move nearly in lockstep. MID charges 0.45%/yr vs 1.00%/yr for TWHIX.

Performance

MID vs. TWHIX - Performance Comparison

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

Returns By Period

In the year-to-date period, MID achieves a 3.23% return, which is significantly lower than TWHIX's 4.04% return.

MID

• 1D: 0.95%
• 1M: 2.66%
• YTD: 3.23%
• 6M: 1.36%
• 1Y: 3.18%
• 3Y*: 13.75%
• 5Y*: 3.97%
• 10Y*: —

TWHIX

• 1D: -1.37%
• 1M: 1.74%
• YTD: 4.04%
• 6M: 1.74%
• 1Y: 2.08%
• 3Y*: 14.42%
• 5Y*: 4.31%
• 10Y*: 12.16%

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

MID vs. TWHIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020
MID American Century Mid Cap Growth Impact ETF	3.23%	8.22%	19.40%	22.20%	-27.44%	10.39%	30.35%
TWHIX American Century Heritage Fund	4.04%	6.53%	24.66%	20.64%	-28.13%	11.52%	31.63%

Correlation

The correlation between MID and TWHIX 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	0.96
Correlation (All Time) Calculated using the full available price history since Jul 15, 2020	0.96

The correlation between MID and TWHIX has been stable across timeframes, ranging from 0.94 to 0.96 - a consistent structural relationship.

Return for Risk

MID vs. TWHIX — Risk / Return Rank

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

MID

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

TWHIX

TWHIX Risk / Return Rank: 4
TWHIX Sharpe Ratio Rank: 4
TWHIX Sortino Ratio Rank: 4
TWHIX Omega Ratio Rank: 4
TWHIX Calmar Ratio Rank: 4
TWHIX Martin Ratio Rank: 5

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. TWHIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Mid Cap Growth Impact ETF (MID) and American Century Heritage Fund (TWHIX). 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	TWHIX	Difference
Sharpe ratio: Return per unit of total volatility	0.18	0.22	-0.03
Sortino ratio: Return per unit of downside risk	0.38	0.43	-0.06
Omega ratio: Gain probability vs. loss probability	1.04	1.05	-0.01
Calmar ratio: Return relative to maximum drawdown	0.23	0.25	-0.02
Martin ratio: Return relative to average drawdown	0.67	0.71	-0.04

MID vs. TWHIX - Sharpe Ratio Comparison

The current MID Sharpe Ratio is 0.18, which is comparable to the TWHIX Sharpe Ratio of 0.22. The chart below compares the historical Sharpe Ratios of MID and TWHIX, 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. TWHIX - Drawdown Comparison

The maximum MID drawdown since its inception was -40.15%, smaller than the maximum TWHIX drawdown of -56.98%. Use the drawdown chart below to compare losses from any high point for MID and TWHIX.

Drawdown Indicators

	MID	TWHIX	Difference
Max Drawdown Largest peak-to-trough decline	-40.15%	-56.98%	+16.83%
Max Drawdown (1Y) Largest decline over 1 year	-13.89%	-15.82%	+1.93%
Max Drawdown (3Y) Largest decline over 3 years	-23.92%	-26.30%	+2.38%
Max Drawdown (5Y) Largest decline over 5 years	-40.15%	-40.34%	+0.19%
Max Drawdown (10Y) Largest decline over 10 years	—	-40.34%	—
Current Drawdown Current decline from peak	-2.82%	-2.74%	-0.08%
Average Drawdown Average peak-to-trough decline	-13.34%	-12.23%	-1.11%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.73%	5.47%	-0.74%

Volatility

MID vs. TWHIX - Volatility Comparison

American Century Mid Cap Growth Impact ETF (MID) and American Century Heritage Fund (TWHIX) have volatilities of 6.61% and 6.63%, 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	TWHIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.61%	6.63%	-0.02%
Volatility (6M) Calculated over the trailing 6-month period	13.91%	14.53%	-0.62%
Volatility (1Y) Calculated over the trailing 1-year period	17.47%	18.13%	-0.66%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	23.72%	23.36%	+0.36%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.92%	22.85%	+1.07%

MID vs. TWHIX - Expense Ratio Comparison

MID has a 0.45% expense ratio, which is lower than TWHIX's 1.00% expense ratio.

Dividends

MID vs. TWHIX - Dividend Comparison

MID's dividend yield for the trailing twelve months is around 0.15%, less than TWHIX's 21.28% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016
MID American Century Mid Cap Growth Impact ETF	0.15%	0.18%	0.17%	0.02%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
TWHIX American Century Heritage Fund	21.28%	22.14%	15.58%	0.78%	0.98%	12.00%	13.72%	11.32%	25.33%	9.38%	8.71%

Frequently Asked Questions

Can I hold both MID and TWHIX in my portfolio?

With a correlation of 0.94, MID and TWHIX 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, MID or TWHIX?

TWHIX has higher volatility (6.63%) compared to MID (6.61%). In terms of maximum drawdown, MID dropped -40.15% vs TWHIX's -56.98%.

Which has better risk-adjusted returns?

TWHIX currently has the higher Sharpe Ratio (0.22 vs 0.18), 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.