FSTDX vs. WAIIX

Last updated Jun 4, 2026

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

Performance

FSTDX vs. WAIIX - Performance Comparison

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

Returns By Period

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

FSTDX

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

FSTDX vs. WAIIX - Yearly Performance Comparison

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

Correlation

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

Return for Risk

FSTDX vs. WAIIX — Risk / Return Rank

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

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

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.

FSTDX vs. WAIIX - Risk-Adjusted Trends Comparison

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

	FSTDX	WAIIX	Difference
Sharpe ratio: Return per unit of total volatility	1.11	1.37	-0.26
Sortino ratio: Return per unit of downside risk	1.66	2.06	-0.40
Omega ratio: Gain probability vs. loss probability	1.20	1.25	-0.05
Calmar ratio: Return relative to maximum drawdown	1.63	2.18	-0.55
Martin ratio: Return relative to average drawdown	4.64	7.31	-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.

FSTDX vs. WAIIX - Sharpe Ratio Comparison

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

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

Drawdowns

FSTDX vs. WAIIX - Drawdown Comparison

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

Drawdown Indicators

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

Volatility

FSTDX vs. WAIIX - Volatility Comparison

Fidelity Series 5+ Year Inflation-Protected Bond Index Fund (FSTDX) has a higher volatility of 1.42% compared to Western Asset Inflation Indexed Plus Bond Fund (WAIIX) at 0.93%. This indicates that FSTDX's price experiences larger fluctuations and is considered to be riskier than WAIIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

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

FSTDX vs. WAIIX - Expense Ratio Comparison

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

Dividends

FSTDX vs. WAIIX - Dividend Comparison

FSTDX's dividend yield for the trailing twelve months is around 3.98%, more than WAIIX's 3.45% 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 FSTDX and WAIIX in my portfolio?

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

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

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.