OPOCX vs. SSKEX

Last updated Jun 25, 2026

OPOCX (Invesco Discovery Fund) and SSKEX (State Street Emerging Markets Equity Index Fund) are both mutual funds - OPOCX is a Small Cap Growth Equities fund managed by Invesco, while SSKEX is a Emerging Markets Diversified fund managed by State Street. Over the past 10 years, OPOCX returned 17.14%/yr vs 10.42%/yr for SSKEX. At a 0.49 correlation, their price movements are largely independent. OPOCX charges 1.01%/yr vs 0.17%/yr for SSKEX.

Performance

OPOCX vs. SSKEX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Invesco Discovery Fund (OPOCX) and State Street Emerging Markets Equity Index Fund (SSKEX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, OPOCX achieves a 34.99% return, which is significantly higher than SSKEX's 25.59% return. Over the past 10 years, OPOCX has outperformed SSKEX with an annualized return of 17.14%, while SSKEX has yielded a comparatively lower 10.42% annualized return.

OPOCX

• 1D: -2.85%
• 1M: 5.70%
• YTD: 34.99%
• 6M: 30.85%
• 1Y: 54.77%
• 3Y*: 27.87%
• 5Y*: 10.33%
• 10Y*: 17.14%

SSKEX

• 1D: -3.92%
• 1M: 3.46%
• YTD: 25.59%
• 6M: 26.77%
• 1Y: 47.05%
• 3Y*: 23.31%
• 5Y*: 7.43%
• 10Y*: 10.42%

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

OPOCX vs. SSKEX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
OPOCX Invesco Discovery Fund	34.99%	16.77%	22.61%	17.02%	-31.26%	14.78%	50.33%	36.81%	-4.15%	29.04%
SSKEX State Street Emerging Markets Equity Index Fund	25.59%	33.79%	7.00%	9.50%	-20.23%	-2.80%	18.20%	18.16%	-14.78%	37.18%

Correlation

The correlation between OPOCX and SSKEX is 0.42, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.42
Correlation (3Y) Calculated over the trailing 3-year period	0.43
Correlation (5Y) Calculated over the trailing 5-year period	0.49
Correlation (10Y) Calculated over the trailing 10-year period	0.49
Correlation (All Time) Calculated using the full available price history since Jan 4, 2016	0.49

Return for Risk

OPOCX vs. SSKEX — Risk / Return Rank

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

OPOCX

OPOCX Risk / Return Rank: 75
OPOCX Sharpe Ratio Rank: 72
OPOCX Sortino Ratio Rank: 59
OPOCX Omega Ratio Rank: 56
OPOCX Calmar Ratio Rank: 94
OPOCX Martin Ratio Rank: 95

SSKEX

SSKEX Risk / Return Rank: 85
SSKEX Sharpe Ratio Rank: 89
SSKEX Sortino Ratio Rank: 77
SSKEX Omega Ratio Rank: 83
SSKEX Calmar Ratio Rank: 88
SSKEX Martin Ratio Rank: 86

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.

OPOCX vs. SSKEX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Invesco Discovery Fund (OPOCX) and State Street Emerging Markets Equity Index Fund (SSKEX). 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.

	OPOCX	SSKEX	Difference
Sharpe ratio: Return per unit of total volatility	2.25	2.63	-0.39
Sortino ratio: Return per unit of downside risk	2.88	3.31	-0.44
Omega ratio: Gain probability vs. loss probability	1.37	1.50	-0.13
Calmar ratio: Return relative to maximum drawdown	5.06	4.06	+1.00
Martin ratio: Return relative to average drawdown	19.78	14.76	+5.02

OPOCX vs. SSKEX - Sharpe Ratio Comparison

The current OPOCX Sharpe Ratio is 2.25, which is comparable to the SSKEX Sharpe Ratio of 2.63. The chart below compares the historical Sharpe Ratios of OPOCX and SSKEX, 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

OPOCX vs. SSKEX - Drawdown Comparison

The maximum OPOCX drawdown since its inception was -64.17%, which is greater than SSKEX's maximum drawdown of -39.23%. Use the drawdown chart below to compare losses from any high point for OPOCX and SSKEX.

Drawdown Indicators

	OPOCX	SSKEX	Difference
Max Drawdown Largest peak-to-trough decline	-64.17%	-39.23%	-24.94%
Max Drawdown (1Y) Largest decline over 1 year	-11.38%	-12.44%	+1.06%
Max Drawdown (3Y) Largest decline over 3 years	-28.60%	-16.09%	-12.51%
Max Drawdown (5Y) Largest decline over 5 years	-43.27%	-36.85%	-6.42%
Max Drawdown (10Y) Largest decline over 10 years	-43.27%	-39.23%	-4.04%
Current Drawdown Current decline from peak	-2.85%	-3.92%	+1.07%
Average Drawdown Average peak-to-trough decline	-18.84%	-13.21%	-5.63%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.90%	3.41%	-0.51%

Volatility

OPOCX vs. SSKEX - Volatility Comparison

The current volatility for Invesco Discovery Fund (OPOCX) is 9.67%, while State Street Emerging Markets Equity Index Fund (SSKEX) has a volatility of 10.82%. This indicates that OPOCX experiences smaller price fluctuations and is considered to be less risky than SSKEX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	OPOCX	SSKEX	Difference
Volatility (1M) Calculated over the trailing 1-month period	9.67%	10.82%	-1.15%
Volatility (6M) Calculated over the trailing 6-month period	21.11%	17.18%	+3.93%
Volatility (1Y) Calculated over the trailing 1-year period	25.68%	19.18%	+6.50%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	25.63%	17.08%	+8.55%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	24.95%	17.50%	+7.45%

OPOCX vs. SSKEX - Expense Ratio Comparison

OPOCX has a 1.01% expense ratio, which is higher than SSKEX's 0.17% expense ratio.

Dividends

OPOCX vs. SSKEX - Dividend Comparison

OPOCX's dividend yield for the trailing twelve months is around 9.94%, more than SSKEX's 2.27% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
OPOCX Invesco Discovery Fund	9.94%	13.41%	6.86%	0.00%	0.00%	20.51%	11.22%	6.42%	18.85%	12.46%	4.33%	6.84%
SSKEX State Street Emerging Markets Equity Index Fund	2.27%	2.85%	2.90%	3.26%	3.90%	1.95%	1.84%	2.84%	3.01%	2.55%	2.29%	0.00%

Frequently Asked Questions

Can I hold both OPOCX and SSKEX in my portfolio?

OPOCX and SSKEX have a correlation of 0.42, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, OPOCX or SSKEX?

SSKEX has higher volatility (10.82%) compared to OPOCX (9.67%). In terms of maximum drawdown, OPOCX dropped -64.17% vs SSKEX's -39.23%.

Which has better risk-adjusted returns?

SSKEX currently has the higher Sharpe Ratio (2.63 vs 2.25), 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.