ACSG vs. MDY

Last updated Jun 24, 2026

ACSG (American Century Small Cap Growth Insights ETF) and MDY (SPDR S&P MidCap 400 ETF) are both exchange-traded funds - ACSG is a Small Cap Growth Equities fund actively managed by American Century, while MDY is a Mid Cap Blend Equities fund tracking the S&P MidCap 400 Index. ACSG is actively managed, while MDY is passively managed. Their correlation of 0.90 suggests significant overlap in exposure. ACSG charges 0.49%/yr vs 0.23%/yr for MDY.

Performance

ACSG vs. MDY - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Small Cap Growth Insights ETF (ACSG) and SPDR S&P MidCap 400 ETF (MDY). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, ACSG achieves a 19.16% return, which is significantly higher than MDY's 14.41% return.

ACSG

• 1D: -1.75%
• 1M: 5.03%
• YTD: 19.16%
• 6M: 16.11%
• 1Y: —
• 3Y*: —
• 5Y*: —
• 10Y*: —

MDY

• 1D: -1.01%
• 1M: 2.67%
• YTD: 14.41%
• 6M: 12.36%
• 1Y: 24.68%
• 3Y*: 15.79%
• 5Y*: 8.21%
• 10Y*: 11.40%

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

ACSG vs. MDY - Yearly Performance Comparison

	2026 (YTD)	2025
ACSG American Century Small Cap Growth Insights ETF	19.16%	-0.86%
MDY SPDR S&P MidCap 400 ETF	14.41%	1.77%

Correlation

The correlation between ACSG and MDY is 0.90, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (All Time) Calculated using the full available price history since Oct 16, 2025	0.90

ACSG vs. MDY - Sectors Allocation Comparison

Sectors	ACSG	MDY
Technology	26.1%	17.4%
Industrials	22.4%	24.8%
Healthcare	21.2%	9.1%
Consumer Cyclical	8.2%	10.7%
Financial Services	7.6%	13.3%
Basic Materials	3.8%	4.9%
Energy	2.8%	5.0%
Consumer Defensive	2.4%	3.4%
Utilities	2.0%	3.0%
Communication Services	1.9%	1.0%
Real Estate	1.8%	7.4%

Return for Risk

ACSG vs. MDY — Risk / Return Rank

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

ACSG

Risk / return metrics aren't available yet — we need at least 12 months of trading data to calculate them.

MDY

MDY Risk / Return Rank: 52
MDY Sharpe Ratio Rank: 47
MDY Sortino Ratio Rank: 48
MDY Omega Ratio Rank: 44
MDY Calmar Ratio Rank: 59
MDY Martin Ratio Rank: 60

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.

ACSG vs. MDY - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Small Cap Growth Insights ETF (ACSG) and SPDR S&P MidCap 400 ETF (MDY). 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.

	ACSG	MDY	Difference
Sharpe ratio: Return per unit of total volatility	—	1.57	—
Sortino ratio: Return per unit of downside risk	—	2.31	—
Omega ratio: Gain probability vs. loss probability	—	1.28	—
Calmar ratio: Return relative to maximum drawdown	—	2.81	—
Martin ratio: Return relative to average drawdown	—	10.23	—

Drawdowns

ACSG vs. MDY - Drawdown Comparison

The maximum ACSG drawdown since its inception was -13.28%, smaller than the maximum MDY drawdown of -55.33%. Use the drawdown chart below to compare losses from any high point for ACSG and MDY.

Drawdown Indicators

	ACSG	MDY	Difference
Max Drawdown Largest peak-to-trough decline	-13.28%	-55.33%	+42.05%
Max Drawdown (1Y) Largest decline over 1 year	—	-8.82%	—
Max Drawdown (3Y) Largest decline over 3 years	—	-24.03%	—
Max Drawdown (5Y) Largest decline over 5 years	—	-24.03%	—
Max Drawdown (10Y) Largest decline over 10 years	—	-42.22%	—
Current Drawdown Current decline from peak	-1.75%	-1.13%	-0.62%
Average Drawdown Average peak-to-trough decline	-2.92%	-7.02%	+4.10%
Ulcer Index Depth and duration of drawdowns from previous peaks	—	2.42%	—

Volatility

Volatility by Period

	ACSG	MDY	Difference
Volatility (1M) Calculated over the trailing 1-month period	—	4.69%	—
Volatility (6M) Calculated over the trailing 6-month period	—	11.70%	—
Volatility (1Y) Calculated over the trailing 1-year period	22.95%	15.81%	+7.14%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.95%	19.78%	+3.17%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.95%	21.18%	+1.77%

ACSG vs. MDY - Expense Ratio Comparison

ACSG has a 0.49% expense ratio, which is higher than MDY's 0.23% expense ratio.

Dividends

ACSG vs. MDY - Dividend Comparison

ACSG has not paid dividends to shareholders, while MDY's dividend yield for the trailing twelve months is around 1.02%.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ACSG American Century Small Cap Growth Insights ETF	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
MDY SPDR S&P MidCap 400 ETF	1.02%	1.15%	1.18%	1.21%	1.37%	0.96%	1.12%	1.34%	1.39%	1.18%	1.31%	1.35%

Frequently Asked Questions

Can I hold both ACSG and MDY in my portfolio?

With a correlation of 0.90, ACSG and MDY 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 ETF is better, ACSG or MDY?

On fees, MDY is cheaper at 0.23% per year. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF is cheaper, ACSG or MDY?

MDY is cheaper with a 0.23% expense ratio, compared with 0.49% for ACSG.

Which ETF pays a higher dividend yield, ACSG or MDY?

MDY has the higher dividend yield at 1.02%, compared with 0.00% for ACSG.

What is the main difference between ACSG and MDY?

ACSG is categorized as Small Cap Growth Equities, while MDY is Mid Cap Blend Equities. They also come from different issuers: American Century and State Street. Their fees differ too: 0.49% for ACSG and 0.23% for MDY.