PSSMX vs. IWM

Last updated Jun 4, 2026

PSSMX (Principal SmallCap S&P 600 Index Fund) and IWM (iShares Russell 2000 ETF) are both Small Cap Blend Equities funds. Over the past 10 years, PSSMX returned 10.83%/yr vs 10.93%/yr for IWM. With a 0.97 correlation, they move nearly in lockstep. PSSMX charges 0.73%/yr vs 0.19%/yr for IWM.

Performance

PSSMX vs. IWM - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Principal SmallCap S&P 600 Index Fund (PSSMX) and iShares Russell 2000 ETF (IWM). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PSSMX achieves a 15.97% return, which is significantly lower than IWM's 17.07% return. Both investments have delivered pretty close results over the past 10 years, with PSSMX having a 10.83% annualized return and IWM not far ahead at 10.93%.

PSSMX

• 1D: 0.85%
• 1M: 2.53%
• YTD: 15.97%
• 6M: 14.78%
• 1Y: 31.83%
• 3Y*: 16.96%
• 5Y*: 6.80%
• 10Y*: 10.83%

IWM

• 1D: -1.37%
• 1M: 3.52%
• YTD: 17.07%
• 6M: 15.83%
• 1Y: 39.10%
• 3Y*: 17.88%
• 5Y*: 6.11%
• 10Y*: 10.93%

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

PSSMX vs. IWM - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PSSMX Principal SmallCap S&P 600 Index Fund	15.97%	5.34%	16.60%	15.18%	-16.69%	25.39%	10.65%	21.99%	-9.42%	12.46%
IWM iShares Russell 2000 ETF	17.07%	12.66%	11.38%	16.83%	-20.48%	14.54%	20.03%	25.39%	-11.12%	14.58%

Correlation

The correlation between PSSMX and IWM is 0.92, 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	0.92
Correlation (3Y) Calculated over the trailing 3-year period	0.95
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (10Y) Calculated over the trailing 10-year period	0.96
Correlation (All Time) Calculated using the full available price history since Jan 3, 2001	0.97

The correlation between PSSMX and IWM has been stable across timeframes, ranging from 0.92 to 0.97 - a consistent structural relationship.

Return for Risk

PSSMX vs. IWM — Risk / Return Rank

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

PSSMX

PSSMX Risk / Return Rank: 56
PSSMX Sharpe Ratio Rank: 45
PSSMX Sortino Ratio Rank: 45
PSSMX Omega Ratio Rank: 40
PSSMX Calmar Ratio Rank: 83
PSSMX Martin Ratio Rank: 67

IWM

IWM Risk / Return Rank: 62
IWM Sharpe Ratio Rank: 59
IWM Sortino Ratio Rank: 59
IWM Omega Ratio Rank: 53
IWM Calmar Ratio Rank: 70
IWM Martin Ratio Rank: 67

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.

PSSMX vs. IWM - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Principal SmallCap S&P 600 Index Fund (PSSMX) and iShares Russell 2000 ETF (IWM). 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.

	PSSMX	IWM	Difference
Sharpe ratio Return per unit of total volatility	1.95	2.05	-0.10
Sortino ratio Return per unit of downside risk	2.84	2.85	-0.02
Omega ratio Gain probability vs. loss probability	1.34	1.34	0.00
Calmar ratio Return relative to maximum drawdown	3.89	3.56	+0.33
Martin ratio Return relative to average drawdown	13.00	12.64	+0.36
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PSSMX vs. IWM - Sharpe Ratio Comparison

The current PSSMX Sharpe Ratio is 1.95, which is comparable to the IWM Sharpe Ratio of 2.05. The chart below compares the historical Sharpe Ratios of PSSMX and IWM, 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

	PSSMX	IWM	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.95	2.05	-0.10
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.31	0.27	+0.04
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.47	0.48	0.00
Sharpe Ratio (All Time) Calculated using the full available price history	0.41	0.37	+0.05

Drawdowns

PSSMX vs. IWM - Drawdown Comparison

The maximum PSSMX drawdown since its inception was -58.43%, roughly equal to the maximum IWM drawdown of -59.05%. Use the drawdown chart below to compare losses from any high point for PSSMX and IWM.

Drawdown Indicators

	PSSMX	IWM	Difference
Max Drawdown Largest peak-to-trough decline	-58.43%	-59.05%	+0.62%
Max Drawdown (1Y) Largest decline over 1 year	-8.76%	-11.03%	+2.27%
Max Drawdown (3Y) Largest decline over 3 years	-24.30%	-27.50%	+3.20%
Max Drawdown (5Y) Largest decline over 5 years	-27.01%	-31.91%	+4.90%
Max Drawdown (10Y) Largest decline over 10 years	-44.85%	-41.13%	-3.72%
Current Drawdown Current decline from peak	-0.07%	-1.49%	+1.42%
Average Drawdown Average peak-to-trough decline	-9.52%	-10.77%	+1.25%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.62%	3.10%	-0.48%

Volatility

PSSMX vs. IWM - Volatility Comparison

The current volatility for Principal SmallCap S&P 600 Index Fund (PSSMX) is 4.47%, while iShares Russell 2000 ETF (IWM) has a volatility of 5.75%. This indicates that PSSMX experiences smaller price fluctuations and is considered to be less risky than IWM based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PSSMX	IWM	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.47%	5.75%	-1.28%
Volatility (6M) Calculated over the trailing 6-month period	11.69%	13.53%	-1.84%
Volatility (1Y) Calculated over the trailing 1-year period	17.46%	19.20%	-1.74%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.76%	22.52%	-0.76%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.92%	23.04%	-0.12%

PSSMX vs. IWM - Expense Ratio Comparison

PSSMX has a 0.73% expense ratio, which is higher than IWM's 0.19% expense ratio.

Dividends

PSSMX vs. IWM - Dividend Comparison

PSSMX's dividend yield for the trailing twelve months is around 8.61%, more than IWM's 0.88% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
IWM iShares Russell 2000 ETF	0.88%	1.04%	1.15%	1.35%	1.48%	0.94%	1.04%	1.26%	1.40%	1.26%	1.38%	1.54%
PSSMX Principal SmallCap S&P 600 Index Fund	8.61%	9.98%	15.91%	3.75%	10.45%	8.23%	1.67%	6.56%	13.08%	6.03%	6.15%	8.07%

Frequently Asked Questions

Can I hold both PSSMX and IWM in my portfolio?

With a correlation of 0.92, PSSMX and IWM 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, PSSMX or IWM?

IWM has higher volatility (5.75%) compared to PSSMX (4.47%). In terms of maximum drawdown, PSSMX dropped -58.43% vs IWM's -59.05%.

Which has better risk-adjusted returns?

IWM currently has the higher Sharpe Ratio (2.05 vs 1.95), 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.