FBLTX vs. ZROZ

Last updated Aug 1, 2026

FBLTX (Fidelity SAI Long-Term Treasury Bond Index Fund) and ZROZ (PIMCO 25+ Year Zero Coupon US Treasury Index Fund) are both Government Bonds funds. Over the past 10 years, FBLTX returned -2.52%/yr vs -5.40%/yr for ZROZ. Their 0.98 correlation means they have historically moved very closely together. FBLTX charges 0.03%/yr vs 0.15%/yr for ZROZ.

Performance

FBLTX vs. ZROZ - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity SAI Long-Term Treasury Bond Index Fund (FBLTX) and PIMCO 25+ Year Zero Coupon US Treasury Index Fund (ZROZ). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FBLTX achieves a -3.37% return, which is significantly higher than ZROZ's -7.23% return. Over the past 10 years, FBLTX has outperformed ZROZ with an annualized return of -2.52%, while ZROZ has yielded a comparatively lower -5.40% annualized return.

FBLTX

• 1D: -0.16%
• 1M: -3.63%
• 6M: -3.28%
• YTD: -3.37%
• 1Y: -2.17%
• 3Y*: -2.29%
• 5Y*: -8.31%
• 10Y*: -2.52%
• ALL TIME*: -1.05%

ZROZ

• 1D: -1.24%
• 1M: -7.20%
• 6M: -6.41%
• YTD: -7.23%
• 1Y: -7.54%
• 3Y*: -8.06%
• 5Y*: -14.47%
• 10Y*: -5.40%
• ALL TIME*: 1.69%

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

Liquidity Comparison

Position	Avg. Volume Value (2W)	Avg. Volume Value (1M)	Avg. Volume Value (3M)
FBLTX Fidelity SAI Long-Term Treasury Bond Index Fund	$0.00	$0.00	$0.00
ZROZ PIMCO 25+ Year Zero Coupon US Treasury Index Fund	$41.31M	$45.82M	$40.38M

FBLTX vs. ZROZ - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FBLTX Fidelity SAI Long-Term Treasury Bond Index Fund	-3.37%	4.39%	-8.05%	2.71%	-31.84%	-4.89%	18.27%	14.36%	-1.24%	9.06%
ZROZ PIMCO 25+ Year Zero Coupon US Treasury Index Fund	-7.23%	-1.84%	-16.18%	1.19%	-41.28%	-5.22%	24.57%	21.22%	-5.43%	14.77%

Correlation

The correlation between FBLTX and ZROZ is 0.94, meaning they have usually moved in the same direction, including during past declines.

	Correlation
Correlation (1Y) Focuses on recent behavior, but can change the most.	0.94
Correlation (3Y) Balances recent behavior with more history.	0.97
Correlation (5Y) Shows whether the relationship held over a longer period.	0.98
Correlation (10Y) Provides a long-term view across more market conditions.	0.98
Correlation (All Time) Calculated using the full available price history since Oct 16, 2015	0.98

The correlation between FBLTX and ZROZ has been stable across timeframes, ranging from 0.94 to 0.98 - a consistent structural relationship.

Return for Risk

FBLTX vs. ZROZ — Risk / Return Rank

Compare historical risk-adjusted metric ranks over the past 12 months.

FBLTX

FBLTX Risk / Return Rank: 4
FBLTX Sharpe Ratio Rank: 4
FBLTX Sortino Ratio Rank: 4
FBLTX Omega Ratio Rank: 4
FBLTX Calmar Ratio Rank: 4
FBLTX Martin Ratio Rank: 4

ZROZ

ZROZ Risk / Return Rank: 6
ZROZ Sharpe Ratio Rank: 6
ZROZ Sortino Ratio Rank: 6
ZROZ Omega Ratio Rank: 6
ZROZ Calmar Ratio Rank: 6
ZROZ Martin Ratio Rank: 5

The rank (0–100) uses a weighted average of the Sharpe, Sortino, Omega, Calmar, and Martin percentile ranks for the trailing 12 months. Higher means stronger historical risk-adjusted performance within the peer group.

FBLTX vs. ZROZ - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity SAI Long-Term Treasury Bond Index Fund (FBLTX) and PIMCO 25+ Year Zero Coupon US Treasury Index Fund (ZROZ). 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.

	FBLTX	ZROZ	Difference
Sharpe ratio: Return per unit of total volatility	-0.04	-0.38	+0.34
Sortino ratio: Return per unit of downside risk	0.01	-0.44	+0.45
Omega ratio: Gain probability vs. loss probability	1.00	0.95	+0.05
Calmar ratio: Return relative to maximum drawdown	-0.05	-0.39	+0.35
Martin ratio: Return relative to average drawdown	-0.10	-0.82	+0.71

FBLTX vs. ZROZ - Sharpe Ratio Comparison

The current FBLTX Sharpe Ratio is -0.04, which is higher than the ZROZ Sharpe Ratio of -0.38. The chart below compares the historical Sharpe Ratios of FBLTX and ZROZ, 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

FBLTX vs. ZROZ - Drawdown Comparison

The maximum FBLTX drawdown since its inception was -49.06%, smaller than the maximum ZROZ drawdown of -62.93%. Use the drawdown chart below to compare losses from any high point for FBLTX and ZROZ.

Drawdown Indicators

	FBLTX	ZROZ	Difference
Max Drawdown Largest peak-to-trough decline	-49.06%	-62.93%	+13.87%
Max Drawdown (1Y) Largest decline over 1 year	-7.66%	-14.90%	+7.24%
Max Drawdown (3Y) Largest decline over 3 years	-14.75%	-26.42%	+11.67%
Max Drawdown (5Y) Largest decline over 5 years	-44.19%	-57.98%	+13.79%
Max Drawdown (10Y) Largest decline over 10 years	-49.06%	-62.93%	+13.87%
Current Drawdown Current decline from peak	-42.95%	-62.42%	+19.47%
Average Drawdown Average peak-to-trough decline	-21.28%	-24.38%	+3.10%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.54%	7.18%	-3.64%

Volatility

FBLTX vs. ZROZ - Volatility Comparison

The current volatility for Fidelity SAI Long-Term Treasury Bond Index Fund (FBLTX) is 2.48%, while PIMCO 25+ Year Zero Coupon US Treasury Index Fund (ZROZ) has a volatility of 4.20%. This indicates that FBLTX experiences smaller price fluctuations and is considered to be less risky than ZROZ based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FBLTX	ZROZ	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.48%	4.20%	-1.72%
Volatility (6M) Calculated over the trailing 6-month period	6.79%	11.11%	-4.32%
Volatility (1Y) Calculated over the trailing 1-year period	9.26%	15.45%	-6.19%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	15.57%	23.76%	-8.19%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	14.51%	21.96%	-7.45%

FBLTX vs. ZROZ - Expense Ratio Comparison

FBLTX has a 0.03% expense ratio, which is lower than ZROZ's 0.15% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

FBLTX vs. ZROZ - Dividend Comparison

FBLTX's dividend yield for the trailing twelve months is around 3.97%, less than ZROZ's 5.59% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FBLTX Fidelity SAI Long-Term Treasury Bond Index Fund	3.97%	4.04%	3.60%	3.29%	2.25%	1.81%	6.73%	2.39%	2.87%	2.68%	3.70%	0.39%
ZROZ PIMCO 25+ Year Zero Coupon US Treasury Index Fund	5.59%	4.96%	4.58%	3.52%	2.76%	1.60%	1.68%	2.22%	2.06%	2.53%	3.00%	2.98%

Frequently Asked Questions

Can I hold both FBLTX and ZROZ in my portfolio?

With a correlation of 0.94, FBLTX and ZROZ 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, FBLTX or ZROZ?

ZROZ has higher volatility (4.20%) compared to FBLTX (2.48%). In terms of maximum drawdown, FBLTX dropped -49.06% vs ZROZ's -62.93%.

Which has better risk-adjusted returns?

FBLTX currently has the higher Sharpe Ratio (-0.04 vs -0.38), 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.