FSPWX vs. WAIIX

Last updated Jun 4, 2026

FSPWX (Fidelity SAI Inflation-Protected Bond Index Fund) and WAIIX (Western Asset Inflation Indexed Plus Bond Fund) are both Inflation-Protected Bonds funds. Over the past year, FSPWX returned 5.38% vs 4.83% for WAIIX. Their correlation of 0.93 suggests significant overlap in exposure. FSPWX charges 0.05%/yr vs 0.54%/yr for WAIIX.

Performance

FSPWX vs. WAIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity SAI Inflation-Protected Bond Index Fund (FSPWX) and Western Asset Inflation Indexed Plus Bond Fund (WAIIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FSPWX achieves a 1.83% return, which is significantly higher than WAIIX's 1.43% return.

FSPWX

• 1D: 0.00%
• 1M: 0.20%
• YTD: 1.83%
• 6M: 1.35%
• 1Y: 5.38%
• 3Y*: —
• 5Y*: —
• 10Y*: —

WAIIX

• 1D: 0.00%
• 1M: 0.10%
• YTD: 1.43%
• 6M: 0.98%
• 1Y: 4.83%
• 3Y*: 3.39%
• 5Y*: 0.54%
• 10Y*: 2.26%

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

FSPWX vs. WAIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024
FSPWX Fidelity SAI Inflation-Protected Bond Index Fund	1.83%	6.76%	-1.32%
WAIIX Western Asset Inflation Indexed Plus Bond Fund	1.43%	6.41%	-1.82%

Correlation

The correlation between FSPWX and WAIIX is 0.95, 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	0.95
Correlation (All Time) Calculated using the full available price history since Aug 23, 2024	0.93

The correlation between FSPWX and WAIIX has been stable across timeframes, ranging from 0.93 to 0.95 - a consistent structural relationship.

Return for Risk

FSPWX vs. WAIIX — Risk / Return Rank

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

FSPWX

FSPWX Risk / Return Rank: 36
FSPWX Sharpe Ratio Rank: 30
FSPWX Sortino Ratio Rank: 33
FSPWX Omega Ratio Rank: 30
FSPWX Calmar Ratio Rank: 49
FSPWX Martin Ratio Rank: 37

WAIIX

WAIIX Risk / Return Rank: 27
WAIIX Sharpe Ratio Rank: 22
WAIIX Sortino Ratio Rank: 24
WAIIX Omega Ratio Rank: 22
WAIIX Calmar Ratio Rank: 33
WAIIX Martin Ratio Rank: 32

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.

FSPWX vs. WAIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity SAI Inflation-Protected Bond Index Fund (FSPWX) and Western Asset Inflation Indexed Plus Bond Fund (WAIIX). 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.

	FSPWX	WAIIX	Difference
Sharpe ratio: Return per unit of total volatility	1.56	1.37	+0.19
Sortino ratio: Return per unit of downside risk	2.39	2.06	+0.33
Omega ratio: Gain probability vs. loss probability	1.29	1.25	+0.04
Calmar ratio: Return relative to maximum drawdown	2.67	2.18	+0.50
Martin ratio: Return relative to average drawdown	8.19	7.31	+0.88
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

FSPWX vs. WAIIX - Sharpe Ratio Comparison

The current FSPWX Sharpe Ratio is 1.56, which is comparable to the WAIIX Sharpe Ratio of 1.37. The chart below compares the historical Sharpe Ratios of FSPWX and WAIIX, 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

	FSPWX	WAIIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.56	1.37	+0.19
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	—	0.08	—
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.40	—
Sharpe Ratio (All Time) Calculated using the full available price history	1.00	0.64	+0.36

Drawdowns

FSPWX vs. WAIIX - Drawdown Comparison

The maximum FSPWX drawdown since its inception was -3.84%, smaller than the maximum WAIIX drawdown of -16.55%. Use the drawdown chart below to compare losses from any high point for FSPWX and WAIIX.

Drawdown Indicators

	FSPWX	WAIIX	Difference
Max Drawdown Largest peak-to-trough decline	-3.84%	-16.55%	+12.71%
Max Drawdown (1Y) Largest decline over 1 year	-1.95%	-2.18%	+0.23%
Max Drawdown (3Y) Largest decline over 3 years	—	-5.85%	—
Max Drawdown (5Y) Largest decline over 5 years	—	-15.99%	—
Max Drawdown (10Y) Largest decline over 10 years	—	-15.99%	—
Current Drawdown Current decline from peak	0.00%	-2.10%	+2.10%
Average Drawdown Average peak-to-trough decline	-0.98%	-3.83%	+2.85%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.64%	0.65%	-0.01%

Volatility

FSPWX vs. WAIIX - Volatility Comparison

Fidelity SAI Inflation-Protected Bond Index Fund (FSPWX) and Western Asset Inflation Indexed Plus Bond Fund (WAIIX) have volatilities of 0.92% and 0.93%, 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

	FSPWX	WAIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.92%	0.93%	-0.01%
Volatility (6M) Calculated over the trailing 6-month period	2.28%	2.39%	-0.11%
Volatility (1Y) Calculated over the trailing 1-year period	3.35%	3.47%	-0.12%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	4.06%	6.39%	-2.33%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.06%	5.65%	-1.59%

FSPWX vs. WAIIX - Expense Ratio Comparison

FSPWX has a 0.05% expense ratio, which is lower than WAIIX's 0.54% expense ratio.

Dividends

FSPWX vs. WAIIX - Dividend Comparison

FSPWX's dividend yield for the trailing twelve months is around 3.76%, more than WAIIX's 3.45% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSPWX Fidelity SAI Inflation-Protected Bond Index Fund	3.76%	4.19%	0.69%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
WAIIX Western Asset Inflation Indexed Plus Bond Fund	3.45%	4.12%	3.44%	2.80%	6.69%	12.25%	1.38%	2.18%	2.82%	2.03%	1.30%	0.37%

Frequently Asked Questions

Can I hold both FSPWX and WAIIX in my portfolio?

With a correlation of 0.95, FSPWX and WAIIX 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, FSPWX or WAIIX?

WAIIX has higher volatility (0.93%) compared to FSPWX (0.92%). In terms of maximum drawdown, FSPWX dropped -3.84% vs WAIIX's -16.55%.

Which has better risk-adjusted returns?

FSPWX currently has the higher Sharpe Ratio (1.56 vs 1.37), 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.