MGK vs. COST

Last updated Jun 14, 2026

MGK (Vanguard Mega Cap Growth ETF) is Large Cap Growth Equities fund tracking the CRSP US Mega Cap Growth Index, while COST (Costco Wholesale Corporation) is a stock. Over the past 10 years, MGK returned 18.85%/yr vs 22.27%/yr for COST. A 0.53 correlation means they provide meaningful diversification when combined.

Performance

MGK vs. COST - Performance Comparison

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

Returns By Period

In the year-to-date period, MGK achieves a 5.33% return, which is significantly lower than COST's 14.24% return. Over the past 10 years, MGK has underperformed COST with an annualized return of 18.85%, while COST has yielded a comparatively higher 22.27% annualized return.

MGK

• 1D: 0.22%
• 1M: -1.87%
• YTD: 5.33%
• 6M: 6.21%
• 1Y: 24.77%
• 3Y*: 24.17%
• 5Y*: 14.87%
• 10Y*: 18.85%

COST

• 1D: 0.68%
• 1M: -6.35%
• YTD: 14.24%
• 6M: 11.38%
• 1Y: -0.24%
• 3Y*: 25.12%
• 5Y*: 22.12%
• 10Y*: 22.27%

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

MGK vs. COST - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MGK Vanguard Mega Cap Growth ETF	5.33%	20.67%	32.94%	51.67%	-33.59%	28.58%	41.01%	37.38%	-2.91%	29.49%
COST Costco Wholesale Corporation	14.24%	-5.39%	39.62%	49.00%	-19.05%	51.82%	32.67%	45.70%	10.60%	22.37%

Correlation

The correlation between MGK and COST is -0.11, meaning they tend to move in opposite directions. This is especially valuable for risk management - when one declines, the other has historically tended to hold steady or rise.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	-0.11
Correlation (3Y) Calculated over the trailing 3-year period	0.32
Correlation (5Y) Calculated over the trailing 5-year period	0.47
Correlation (10Y) Calculated over the trailing 10-year period	0.48
Correlation (All Time) Calculated using the full available price history since Dec 27, 2007	0.53

The correlation between MGK and COST shifts across timeframes, from -0.11 (1 year) to 0.53 (all time), reflecting how their relationship changes across market environments.

Return for Risk

MGK vs. COST — Risk / Return Rank

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

MGK

MGK Risk / Return Rank: 39
MGK Sharpe Ratio Rank: 44
MGK Sortino Ratio Rank: 42
MGK Omega Ratio Rank: 42
MGK Calmar Ratio Rank: 31
MGK Martin Ratio Rank: 35

COST

COST Risk / Return Rank: 37
COST Sharpe Ratio Rank: 40
COST Sortino Ratio Rank: 32
COST Omega Ratio Rank: 32
COST Calmar Ratio Rank: 40
COST Martin Ratio Rank: 39

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.

MGK vs. COST - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Mega Cap Growth ETF (MGK) and Costco Wholesale Corporation (COST). 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.

	MGK	COST	Difference
Sharpe ratio: Return per unit of total volatility	1.37	-0.08	+1.45
Sortino ratio: Return per unit of downside risk	1.89	0.02	+1.87
Omega ratio: Gain probability vs. loss probability	1.24	1.00	+0.24
Calmar ratio: Return relative to maximum drawdown	1.37	-0.10	+1.47
Martin ratio: Return relative to average drawdown	4.65	-0.22	+4.87

MGK vs. COST - Sharpe Ratio Comparison

The current MGK Sharpe Ratio is 1.37, which is higher than the COST Sharpe Ratio of -0.08. The chart below compares the historical Sharpe Ratios of MGK and COST, 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

MGK vs. COST - Drawdown Comparison

The maximum MGK drawdown since its inception was -48.43%, smaller than the maximum COST drawdown of -53.39%. Use the drawdown chart below to compare losses from any high point for MGK and COST.

Drawdown Indicators

	MGK	COST	Difference
Max Drawdown Largest peak-to-trough decline	-48.43%	-53.39%	+4.96%
Max Drawdown (1Y) Largest decline over 1 year	-16.85%	-15.14%	-1.71%
Max Drawdown (3Y) Largest decline over 3 years	-23.36%	-20.74%	-2.62%
Max Drawdown (5Y) Largest decline over 5 years	-36.01%	-31.40%	-4.61%
Max Drawdown (10Y) Largest decline over 10 years	-36.01%	-31.40%	-4.61%
Current Drawdown Current decline from peak	-5.63%	-10.23%	+4.60%
Average Drawdown Average peak-to-trough decline	-7.58%	-13.36%	+5.78%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.97%	6.67%	-1.70%

Volatility

MGK vs. COST - Volatility Comparison

The current volatility for Vanguard Mega Cap Growth ETF (MGK) is 5.96%, while Costco Wholesale Corporation (COST) has a volatility of 7.44%. This indicates that MGK experiences smaller price fluctuations and is considered to be less risky than COST based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MGK	COST	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.96%	7.44%	-1.48%
Volatility (6M) Calculated over the trailing 6-month period	13.29%	14.53%	-1.24%
Volatility (1Y) Calculated over the trailing 1-year period	16.87%	18.80%	-1.93%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.72%	22.72%	0.00%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.93%	21.95%	-0.02%

Dividends

MGK vs. COST - Dividend Comparison

MGK's dividend yield for the trailing twelve months is around 0.33%, less than COST's 0.55% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
COST Costco Wholesale Corporation	0.55%	0.59%	0.49%	2.87%	0.76%	0.54%	3.38%	0.86%	1.08%	4.81%	1.09%	4.06%
MGK Vanguard Mega Cap Growth ETF	0.33%	0.35%	0.43%	0.50%	0.70%	0.41%	0.65%	0.85%	1.12%	1.23%	1.53%	1.43%

Frequently Asked Questions

Can I hold both MGK and COST in my portfolio?

MGK and COST have a correlation of -0.11, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MGK or COST?

COST has higher volatility (7.44%) compared to MGK (5.96%). In terms of maximum drawdown, MGK dropped -48.43% vs COST's -53.39%.

Which has better risk-adjusted returns?

MGK currently has the higher Sharpe Ratio (1.37 vs -0.08), 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.