TWCGX vs. MGK

Last updated Jun 26, 2026

TWCGX (American Century Growth Fund) and MGK (Vanguard Mega Cap Growth ETF) are both Large Cap Growth Equities funds. Over the past 10 years, TWCGX returned 16.61%/yr vs 19.01%/yr for MGK. With a 0.98 correlation, they move nearly in lockstep. TWCGX charges 0.94%/yr vs 0.05%/yr for MGK.

Performance

TWCGX vs. MGK - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Growth Fund (TWCGX) and Vanguard Mega Cap Growth ETF (MGK). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, TWCGX achieves a 1.23% return, which is significantly lower than MGK's 2.27% return. Over the past 10 years, TWCGX has underperformed MGK with an annualized return of 16.61%, while MGK has yielded a comparatively higher 19.01% annualized return.

TWCGX

• 1D: -0.16%
• 1M: -4.06%
• YTD: 1.23%
• 6M: -0.12%
• 1Y: 15.24%
• 3Y*: 18.62%
• 5Y*: 10.38%
• 10Y*: 16.61%

MGK

• 1D: -0.97%
• 1M: -5.95%
• YTD: 2.27%
• 6M: 0.80%
• 1Y: 17.76%
• 3Y*: 23.32%
• 5Y*: 13.54%
• 10Y*: 19.01%

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

TWCGX vs. MGK - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
TWCGX American Century Growth Fund	1.23%	15.28%	26.20%	43.31%	-31.39%	27.86%	35.23%	35.39%	-1.27%	30.06%
MGK Vanguard Mega Cap Growth ETF	2.27%	20.67%	32.94%	51.67%	-33.59%	28.58%	41.01%	37.38%	-2.91%	29.49%

Correlation

The correlation between TWCGX and MGK is 0.98 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.98
Correlation (3Y) Calculated over the trailing 3-year period	0.99
Correlation (5Y) Calculated over the trailing 5-year period	0.99
Correlation (10Y) Calculated over the trailing 10-year period	0.99
Correlation (All Time) Calculated using the full available price history since Dec 27, 2007	0.98

The correlation between TWCGX and MGK has been stable across timeframes, ranging from 0.98 to 0.99 - a consistent structural relationship.

Return for Risk

TWCGX vs. MGK — Risk / Return Rank

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

TWCGX

TWCGX Risk / Return Rank: 15
TWCGX Sharpe Ratio Rank: 17
TWCGX Sortino Ratio Rank: 16
TWCGX Omega Ratio Rank: 16
TWCGX Calmar Ratio Rank: 12
TWCGX Martin Ratio Rank: 13

MGK

MGK Risk / Return Rank: 29
MGK Sharpe Ratio Rank: 31
MGK Sortino Ratio Rank: 30
MGK Omega Ratio Rank: 30
MGK Calmar Ratio Rank: 24
MGK Martin Ratio Rank: 28

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.

TWCGX vs. MGK - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Growth Fund (TWCGX) and Vanguard Mega Cap Growth ETF (MGK). 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.

	TWCGX	MGK	Difference
Sharpe ratio: Return per unit of total volatility	0.95	1.03	-0.09
Sortino ratio: Return per unit of downside risk	1.36	1.48	-0.12
Omega ratio: Gain probability vs. loss probability	1.17	1.19	-0.01
Calmar ratio: Return relative to maximum drawdown	0.94	1.06	-0.12
Martin ratio: Return relative to average drawdown	3.02	3.51	-0.49

TWCGX vs. MGK - Sharpe Ratio Comparison

The current TWCGX Sharpe Ratio is 0.95, which is comparable to the MGK Sharpe Ratio of 1.03. The chart below compares the historical Sharpe Ratios of TWCGX and MGK, 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

TWCGX vs. MGK - Drawdown Comparison

The maximum TWCGX drawdown since its inception was -59.60%, which is greater than MGK's maximum drawdown of -48.43%. Use the drawdown chart below to compare losses from any high point for TWCGX and MGK.

Drawdown Indicators

	TWCGX	MGK	Difference
Max Drawdown Largest peak-to-trough decline	-59.60%	-48.43%	-11.17%
Max Drawdown (1Y) Largest decline over 1 year	-16.69%	-16.85%	+0.16%
Max Drawdown (3Y) Largest decline over 3 years	-24.20%	-23.36%	-0.84%
Max Drawdown (5Y) Largest decline over 5 years	-34.92%	-36.01%	+1.09%
Max Drawdown (10Y) Largest decline over 10 years	-34.92%	-36.01%	+1.09%
Current Drawdown Current decline from peak	-7.24%	-8.37%	+1.13%
Average Drawdown Average peak-to-trough decline	-15.28%	-7.58%	-7.70%
Ulcer Index Depth and duration of drawdowns from previous peaks	5.17%	5.07%	+0.10%

Volatility

TWCGX vs. MGK - Volatility Comparison

The current volatility for American Century Growth Fund (TWCGX) is 6.57%, while Vanguard Mega Cap Growth ETF (MGK) has a volatility of 7.03%. This indicates that TWCGX experiences smaller price fluctuations and is considered to be less risky than MGK based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TWCGX	MGK	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.57%	7.03%	-0.46%
Volatility (6M) Calculated over the trailing 6-month period	12.98%	13.71%	-0.73%
Volatility (1Y) Calculated over the trailing 1-year period	16.64%	17.27%	-0.63%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.73%	22.81%	-1.08%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.36%	21.95%	-0.59%

TWCGX vs. MGK - Expense Ratio Comparison

TWCGX has a 0.94% expense ratio, which is higher than MGK's 0.05% expense ratio.

Dividends

TWCGX vs. MGK - Dividend Comparison

TWCGX's dividend yield for the trailing twelve months is around 16.93%, more than MGK's 0.34% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MGK Vanguard Mega Cap Growth ETF	0.34%	0.35%	0.43%	0.50%	0.70%	0.41%	0.65%	0.85%	1.12%	1.23%	1.53%	1.43%
TWCGX American Century Growth Fund	16.93%	17.14%	5.96%	4.81%	4.86%	9.83%	5.33%	5.60%	14.07%	10.28%	4.64%	6.80%

Frequently Asked Questions

Can I hold both TWCGX and MGK in my portfolio?

With a correlation of 0.98, TWCGX and MGK 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, TWCGX or MGK?

MGK has higher volatility (7.03%) compared to TWCGX (6.57%). In terms of maximum drawdown, TWCGX dropped -59.60% vs MGK's -48.43%.

Which has better risk-adjusted returns?

MGK currently has the higher Sharpe Ratio (1.03 vs 0.95), 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.