WAIIX vs. FSTDX

Last updated Jun 4, 2026

WAIIX (Western Asset Inflation Indexed Plus Bond Fund) and FSTDX (Fidelity Series 5+ Year Inflation-Protected Bond Index Fund) are both Inflation-Protected Bonds funds. Over the past 3 years, WAIIX returned 3.39%/yr vs 2.89%/yr for FSTDX. With a 0.97 correlation, they move nearly in lockstep. WAIIX charges 0.54%/yr vs 0.00%/yr for FSTDX.

Performance

WAIIX vs. FSTDX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Western Asset Inflation Indexed Plus Bond Fund (WAIIX) and Fidelity Series 5+ Year Inflation-Protected Bond Index Fund (FSTDX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with WAIIX having a 1.43% return and FSTDX slightly higher at 1.50%.

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%

FSTDX

• 1D: 0.00%
• 1M: 0.26%
• YTD: 1.50%
• 6M: 0.69%
• 1Y: 5.99%
• 3Y*: 2.89%
• 5Y*: —
• 10Y*: —

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

WAIIX vs. FSTDX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021
WAIIX Western Asset Inflation Indexed Plus Bond Fund	1.43%	6.41%	1.05%	3.30%	-12.64%	1.32%
FSTDX Fidelity Series 5+ Year Inflation-Protected Bond Index Fund	1.50%	7.38%	-0.43%	2.84%	-19.06%	2.10%

Correlation

The correlation between WAIIX and FSTDX is 0.93, 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	0.93
Correlation (3Y) Calculated over the trailing 3-year period	0.96
Correlation (All Time) Calculated using the full available price history since Aug 17, 2021	0.97

The correlation between WAIIX and FSTDX has been stable across timeframes, ranging from 0.93 to 0.97 - a consistent structural relationship.

Return for Risk

WAIIX vs. FSTDX — Risk / Return Rank

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

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

FSTDX

FSTDX Risk / Return Rank: 17
FSTDX Sharpe Ratio Rank: 16
FSTDX Sortino Ratio Rank: 16
FSTDX Omega Ratio Rank: 14
FSTDX Calmar Ratio Rank: 20
FSTDX Martin Ratio Rank: 17

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.

WAIIX vs. FSTDX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Western Asset Inflation Indexed Plus Bond Fund (WAIIX) and Fidelity Series 5+ Year Inflation-Protected Bond Index Fund (FSTDX). 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.

	WAIIX	FSTDX	Difference
Sharpe ratio: Return per unit of total volatility	1.37	1.11	+0.26
Sortino ratio: Return per unit of downside risk	2.06	1.66	+0.40
Omega ratio: Gain probability vs. loss probability	1.25	1.20	+0.05
Calmar ratio: Return relative to maximum drawdown	2.18	1.63	+0.55
Martin ratio: Return relative to average drawdown	7.31	4.64	+2.67
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

WAIIX vs. FSTDX - Sharpe Ratio Comparison

The current WAIIX Sharpe Ratio is 1.37, which is comparable to the FSTDX Sharpe Ratio of 1.11. The chart below compares the historical Sharpe Ratios of WAIIX and FSTDX, 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

	WAIIX	FSTDX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.37	1.11	+0.26
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	0.64	-0.18	+0.82

Drawdowns

WAIIX vs. FSTDX - Drawdown Comparison

The maximum WAIIX drawdown since its inception was -16.55%, smaller than the maximum FSTDX drawdown of -24.29%. Use the drawdown chart below to compare losses from any high point for WAIIX and FSTDX.

Drawdown Indicators

	WAIIX	FSTDX	Difference
Max Drawdown Largest peak-to-trough decline	-16.55%	-24.29%	+7.74%
Max Drawdown (1Y) Largest decline over 1 year	-2.18%	-3.60%	+1.42%
Max Drawdown (3Y) Largest decline over 3 years	-5.85%	-8.73%	+2.88%
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	-2.10%	-10.45%	+8.35%
Average Drawdown Average peak-to-trough decline	-3.83%	-14.04%	+10.21%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.65%	1.26%	-0.61%

Volatility

WAIIX vs. FSTDX - Volatility Comparison

The current volatility for Western Asset Inflation Indexed Plus Bond Fund (WAIIX) is 0.93%, while Fidelity Series 5+ Year Inflation-Protected Bond Index Fund (FSTDX) has a volatility of 1.42%. This indicates that WAIIX experiences smaller price fluctuations and is considered to be less risky than FSTDX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WAIIX	FSTDX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.93%	1.42%	-0.49%
Volatility (6M) Calculated over the trailing 6-month period	2.39%	3.63%	-1.24%
Volatility (1Y) Calculated over the trailing 1-year period	3.47%	5.31%	-1.84%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.39%	9.46%	-3.07%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.65%	9.46%	-3.81%

WAIIX vs. FSTDX - Expense Ratio Comparison

WAIIX has a 0.54% expense ratio, which is higher than FSTDX's 0.00% expense ratio.

Dividends

WAIIX vs. FSTDX - Dividend Comparison

WAIIX's dividend yield for the trailing twelve months is around 3.45%, less than FSTDX's 3.98% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSTDX Fidelity Series 5+ Year Inflation-Protected Bond Index Fund	3.98%	4.38%	3.58%	3.28%	6.69%	0.88%	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 WAIIX and FSTDX in my portfolio?

With a correlation of 0.93, WAIIX and FSTDX 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, WAIIX or FSTDX?

FSTDX has higher volatility (1.42%) compared to WAIIX (0.93%). In terms of maximum drawdown, WAIIX dropped -16.55% vs FSTDX's -24.29%.

Which has better risk-adjusted returns?

WAIIX currently has the higher Sharpe Ratio (1.37 vs 1.11), 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.