VIMSX vs. OTCKX

Last updated Jun 4, 2026

VIMSX (Vanguard Mid Cap Index Fund) and OTCKX (MFS Mid Cap Growth Fund Class R6) are both mutual funds - VIMSX is a Mid Cap Blend Equities fund managed by Vanguard, while OTCKX is a Mid Cap Growth Equities fund actively managed by MFS. Over the past 10 years, VIMSX returned 11.40%/yr vs 12.88%/yr for OTCKX. Their correlation of 0.90 suggests significant overlap in exposure. VIMSX charges 0.17%/yr vs 0.65%/yr for OTCKX.

Performance

VIMSX vs. OTCKX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Mid Cap Index Fund (VIMSX) and MFS Mid Cap Growth Fund Class R6 (OTCKX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VIMSX achieves a 10.48% return, which is significantly higher than OTCKX's 4.99% return. Over the past 10 years, VIMSX has underperformed OTCKX with an annualized return of 11.40%, while OTCKX has yielded a comparatively higher 12.88% annualized return.

VIMSX

• 1D: 0.90%
• 1M: 3.66%
• YTD: 10.48%
• 6M: 10.13%
• 1Y: 18.59%
• 3Y*: 16.52%
• 5Y*: 7.88%
• 10Y*: 11.40%

OTCKX

• 1D: 0.57%
• 1M: 3.79%
• YTD: 4.99%
• 6M: 3.62%
• 1Y: 4.66%
• 3Y*: 15.51%
• 5Y*: 6.61%
• 10Y*: 12.88%

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

VIMSX vs. OTCKX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VIMSX Vanguard Mid Cap Index Fund	10.48%	11.08%	14.52%	16.40%	-18.80%	24.36%	18.04%	30.85%	-9.35%	19.12%
OTCKX MFS Mid Cap Growth Fund Class R6	4.99%	3.75%	26.48%	21.50%	-28.29%	14.09%	35.81%	37.93%	1.19%	26.35%

Correlation

The correlation between VIMSX and OTCKX is 0.84, 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	0.84
Correlation (3Y) Calculated over the trailing 3-year period	0.86
Correlation (5Y) Calculated over the trailing 5-year period	0.90
Correlation (10Y) Calculated over the trailing 10-year period	0.89
Correlation (All Time) Calculated using the full available price history since Jan 3, 2014	0.90

The correlation between VIMSX and OTCKX has been stable across timeframes, ranging from 0.84 to 0.90 - a consistent structural relationship.

Return for Risk

VIMSX vs. OTCKX — Risk / Return Rank

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

VIMSX

VIMSX Risk / Return Rank: 35
VIMSX Sharpe Ratio Rank: 31
VIMSX Sortino Ratio Rank: 30
VIMSX Omega Ratio Rank: 29
VIMSX Calmar Ratio Rank: 41
VIMSX Martin Ratio Rank: 44

OTCKX

OTCKX Risk / Return Rank: 5
OTCKX Sharpe Ratio Rank: 5
OTCKX Sortino Ratio Rank: 5
OTCKX Omega Ratio Rank: 4
OTCKX Calmar Ratio Rank: 5
OTCKX 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.

VIMSX vs. OTCKX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Mid Cap Index Fund (VIMSX) and MFS Mid Cap Growth Fund Class R6 (OTCKX). 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.

	VIMSX	OTCKX	Difference
Sharpe ratio: Return per unit of total volatility	1.60	0.33	+1.27
Sortino ratio: Return per unit of downside risk	2.29	0.58	+1.71
Omega ratio: Gain probability vs. loss probability	1.28	1.07	+0.21
Calmar ratio: Return relative to maximum drawdown	2.42	0.33	+2.09
Martin ratio: Return relative to average drawdown	9.19	0.86	+8.33
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VIMSX vs. OTCKX - Sharpe Ratio Comparison

The current VIMSX Sharpe Ratio is 1.60, which is higher than the OTCKX Sharpe Ratio of 0.33. The chart below compares the historical Sharpe Ratios of VIMSX and OTCKX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	VIMSX	OTCKX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.60	0.33	+1.27
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.45	0.33	+0.12
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.60	0.64	-0.04
Sharpe Ratio (All Time) Calculated using the full available price history	0.48	0.60	-0.13

Drawdowns

VIMSX vs. OTCKX - Drawdown Comparison

The maximum VIMSX drawdown since its inception was -58.96%, which is greater than OTCKX's maximum drawdown of -36.64%. Use the drawdown chart below to compare losses from any high point for VIMSX and OTCKX.

Drawdown Indicators

	VIMSX	OTCKX	Difference
Max Drawdown Largest peak-to-trough decline	-58.96%	-36.64%	-22.32%
Max Drawdown (1Y) Largest decline over 1 year	-8.14%	-16.31%	+8.17%
Max Drawdown (3Y) Largest decline over 3 years	-19.31%	-20.99%	+1.68%
Max Drawdown (5Y) Largest decline over 5 years	-27.63%	-36.64%	+9.01%
Max Drawdown (10Y) Largest decline over 10 years	-39.29%	-36.64%	-2.65%
Current Drawdown Current decline from peak	0.00%	-2.80%	+2.80%
Average Drawdown Average peak-to-trough decline	-8.07%	-7.36%	-0.71%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.14%	6.29%	-4.15%

Volatility

VIMSX vs. OTCKX - Volatility Comparison

The current volatility for Vanguard Mid Cap Index Fund (VIMSX) is 2.97%, while MFS Mid Cap Growth Fund Class R6 (OTCKX) has a volatility of 4.21%. This indicates that VIMSX experiences smaller price fluctuations and is considered to be less risky than OTCKX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VIMSX	OTCKX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.97%	4.21%	-1.24%
Volatility (6M) Calculated over the trailing 6-month period	9.28%	13.34%	-4.06%
Volatility (1Y) Calculated over the trailing 1-year period	12.30%	16.54%	-4.24%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.64%	20.37%	-2.73%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.93%	20.07%	-1.14%

VIMSX vs. OTCKX - Expense Ratio Comparison

VIMSX has a 0.17% expense ratio, which is lower than OTCKX's 0.65% expense ratio.

Dividends

VIMSX vs. OTCKX - Dividend Comparison

VIMSX's dividend yield for the trailing twelve months is around 1.23%, less than OTCKX's 14.18% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
OTCKX MFS Mid Cap Growth Fund Class R6	14.18%	14.88%	16.85%	0.00%	0.00%	3.35%	0.77%	0.81%	4.40%	8.28%	5.38%	2.72%
VIMSX Vanguard Mid Cap Index Fund	1.23%	1.03%	1.37%	1.39%	1.46%	1.00%	1.34%	1.37%	1.68%	1.24%	1.34%	1.33%

Frequently Asked Questions

Can I hold both VIMSX and OTCKX in my portfolio?

VIMSX and OTCKX have a correlation of 0.84, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VIMSX or OTCKX?

OTCKX has higher volatility (4.21%) compared to VIMSX (2.97%). In terms of maximum drawdown, VIMSX dropped -58.96% vs OTCKX's -36.64%.

Which has better risk-adjusted returns?

VIMSX currently has the higher Sharpe Ratio (1.60 vs 0.33), 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.