WISIX vs. FSTSX

Last updated Jun 4, 2026

WISIX (William Blair International Small Cap Growth Fund) and FSTSX (Fidelity Series International Small Cap Fund) are both Foreign Small & Mid Cap Equities funds. Over the past 10 years, WISIX returned 6.04%/yr vs 9.90%/yr for FSTSX. Their correlation of 0.88 suggests significant overlap in exposure. WISIX charges 1.23%/yr vs 0.03%/yr for FSTSX.

Performance

WISIX vs. FSTSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in William Blair International Small Cap Growth Fund (WISIX) and Fidelity Series International Small Cap Fund (FSTSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, WISIX achieves a 12.59% return, which is significantly higher than FSTSX's 7.71% return. Over the past 10 years, WISIX has underperformed FSTSX with an annualized return of 6.04%, while FSTSX has yielded a comparatively higher 9.90% annualized return.

WISIX

• 1D: -0.31%
• 1M: 1.67%
• YTD: 12.59%
• 6M: 15.43%
• 1Y: 13.37%
• 3Y*: 10.92%
• 5Y*: 0.64%
• 10Y*: 6.04%

FSTSX

• 1D: 0.47%
• 1M: 2.77%
• YTD: 7.71%
• 6M: 10.35%
• 1Y: 18.27%
• 3Y*: 15.84%
• 5Y*: 6.40%
• 10Y*: 9.90%

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

WISIX vs. FSTSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
WISIX William Blair International Small Cap Growth Fund	12.59%	15.31%	0.80%	14.72%	-34.99%	11.01%	29.09%	34.22%	-24.27%	32.71%
FSTSX Fidelity Series International Small Cap Fund	7.71%	27.49%	4.97%	18.36%	-26.25%	18.29%	19.61%	28.24%	-13.19%	34.44%

Correlation

The correlation between WISIX and FSTSX is 0.80, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.85
Correlation (5Y) Calculated over the trailing 5-year period	0.88
Correlation (10Y) Calculated over the trailing 10-year period	0.88
Correlation (All Time) Calculated using the full available price history since Dec 7, 2009	0.88

The correlation between WISIX and FSTSX has been stable across timeframes, ranging from 0.80 to 0.88 - a consistent structural relationship.

Return for Risk

WISIX vs. FSTSX — Risk / Return Rank

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

WISIX

WISIX Risk / Return Rank: 12
WISIX Sharpe Ratio Rank: 12
WISIX Sortino Ratio Rank: 12
WISIX Omega Ratio Rank: 13
WISIX Calmar Ratio Rank: 14
WISIX Martin Ratio Rank: 12

FSTSX

FSTSX Risk / Return Rank: 20
FSTSX Sharpe Ratio Rank: 20
FSTSX Sortino Ratio Rank: 20
FSTSX Omega Ratio Rank: 20
FSTSX Calmar Ratio Rank: 19
FSTSX Martin Ratio Rank: 20

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.

WISIX vs. FSTSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for William Blair International Small Cap Growth Fund (WISIX) and Fidelity Series International Small Cap Fund (FSTSX). 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.

	WISIX	FSTSX	Difference
Sharpe ratio: Return per unit of total volatility	0.93	1.28	-0.35
Sortino ratio: Return per unit of downside risk	1.37	1.88	-0.51
Omega ratio: Gain probability vs. loss probability	1.18	1.23	-0.05
Calmar ratio: Return relative to maximum drawdown	1.26	1.59	-0.33
Martin ratio: Return relative to average drawdown	3.49	5.37	-1.88
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

WISIX vs. FSTSX - Sharpe Ratio Comparison

The current WISIX Sharpe Ratio is 0.93, which is comparable to the FSTSX Sharpe Ratio of 1.28. The chart below compares the historical Sharpe Ratios of WISIX and FSTSX, 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

	WISIX	FSTSX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.93	1.28	-0.35
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.04	0.39	-0.35
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.35	0.62	-0.27
Sharpe Ratio (All Time) Calculated using the full available price history	0.35	0.62	-0.27

Drawdowns

WISIX vs. FSTSX - Drawdown Comparison

The maximum WISIX drawdown since its inception was -64.84%, which is greater than FSTSX's maximum drawdown of -38.91%. Use the drawdown chart below to compare losses from any high point for WISIX and FSTSX.

Drawdown Indicators

	WISIX	FSTSX	Difference
Max Drawdown Largest peak-to-trough decline	-64.84%	-38.91%	-25.93%
Max Drawdown (1Y) Largest decline over 1 year	-10.09%	-11.22%	+1.13%
Max Drawdown (3Y) Largest decline over 3 years	-17.90%	-14.47%	-3.43%
Max Drawdown (5Y) Largest decline over 5 years	-47.76%	-38.91%	-8.85%
Max Drawdown (10Y) Largest decline over 10 years	-47.76%	-38.91%	-8.85%
Current Drawdown Current decline from peak	-9.75%	-1.08%	-8.67%
Average Drawdown Average peak-to-trough decline	-16.57%	-7.89%	-8.68%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.62%	3.30%	+0.32%

Volatility

WISIX vs. FSTSX - Volatility Comparison

William Blair International Small Cap Growth Fund (WISIX) and Fidelity Series International Small Cap Fund (FSTSX) have volatilities of 4.53% and 4.43%, 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

	WISIX	FSTSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.53%	4.43%	+0.10%
Volatility (6M) Calculated over the trailing 6-month period	11.48%	11.06%	+0.42%
Volatility (1Y) Calculated over the trailing 1-year period	13.72%	13.93%	-0.21%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.29%	16.42%	+0.87%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.36%	15.94%	+1.42%

WISIX vs. FSTSX - Expense Ratio Comparison

WISIX has a 1.23% expense ratio, which is higher than FSTSX's 0.03% expense ratio.

Dividends

WISIX vs. FSTSX - Dividend Comparison

WISIX's dividend yield for the trailing twelve months is around 0.54%, less than FSTSX's 14.15% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSTSX Fidelity Series International Small Cap Fund	14.15%	15.24%	10.22%	3.34%	6.38%	13.22%	0.81%	4.27%	10.99%	6.30%	4.01%	7.32%
WISIX William Blair International Small Cap Growth Fund	0.54%	0.61%	1.78%	0.88%	0.21%	16.20%	2.09%	0.31%	13.84%	9.94%	0.36%	2.31%

Frequently Asked Questions

Can I hold both WISIX and FSTSX in my portfolio?

WISIX and FSTSX have a correlation of 0.80, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, WISIX or FSTSX?

WISIX has higher volatility (4.53%) compared to FSTSX (4.43%). In terms of maximum drawdown, WISIX dropped -64.84% vs FSTSX's -38.91%.

Which has better risk-adjusted returns?

FSTSX currently has the higher Sharpe Ratio (1.28 vs 0.93), 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.