VBILX vs. SSAFX

Last updated Jun 24, 2026

VBILX (Vanguard Intermediate-Term Bond Index Fund Admiral Shares) and SSAFX (State Street Aggregate Bond Index Portfolio) are both Intermediate Core Bond funds. Over the past 10 years, VBILX returned 1.79%/yr vs 27.74%/yr for SSAFX. Their correlation of 0.92 suggests significant overlap in exposure. VBILX charges 0.06%/yr vs 0.02%/yr for SSAFX.

Performance

VBILX vs. SSAFX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Intermediate-Term Bond Index Fund Admiral Shares (VBILX) and State Street Aggregate Bond Index Portfolio (SSAFX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VBILX achieves a -0.53% return, which is significantly lower than SSAFX's 0.33% return. Over the past 10 years, VBILX has underperformed SSAFX with an annualized return of 1.79%, while SSAFX has yielded a comparatively higher 27.74% annualized return.

VBILX

• 1D: -0.29%
• 1M: 0.47%
• YTD: -0.53%
• 6M: -0.08%
• 1Y: 3.75%
• 3Y*: 4.34%
• 5Y*: 0.09%
• 10Y*: 1.79%

SSAFX

• 1D: -0.29%
• 1M: 0.60%
• YTD: 0.33%
• 6M: 0.47%
• 1Y: 4.23%
• 3Y*: 3.80%
• 5Y*: -0.06%
• 10Y*: 27.74%

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

VBILX vs. SSAFX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VBILX Vanguard Intermediate-Term Bond Index Fund Admiral Shares	-0.53%	8.57%	1.54%	6.09%	-13.59%	-2.36%	9.82%	10.20%	-0.15%	3.86%
SSAFX State Street Aggregate Bond Index Portfolio	0.33%	6.81%	1.34%	5.61%	-13.30%	-1.72%	978.57%	8.69%	-0.12%	3.38%

Correlation

The correlation between VBILX and SSAFX 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	0.92
Correlation (All Time) Calculated using the full available price history since Sep 22, 2014	0.92

The correlation between VBILX and SSAFX has been stable across timeframes, ranging from 0.92 to 0.96 - a consistent structural relationship.

Return for Risk

VBILX vs. SSAFX — Risk / Return Rank

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

VBILX

VBILX Risk / Return Rank: 14
VBILX Sharpe Ratio Rank: 14
VBILX Sortino Ratio Rank: 15
VBILX Omega Ratio Rank: 13
VBILX Calmar Ratio Rank: 14
VBILX Martin Ratio Rank: 12

SSAFX

SSAFX Risk / Return Rank: 21
SSAFX Sharpe Ratio Rank: 21
SSAFX Sortino Ratio Rank: 22
SSAFX Omega Ratio Rank: 19
SSAFX Calmar Ratio Rank: 23
SSAFX Martin Ratio Rank: 20

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.

VBILX vs. SSAFX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Intermediate-Term Bond Index Fund Admiral Shares (VBILX) and State Street Aggregate Bond Index Portfolio (SSAFX). 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.

	VBILX	SSAFX	Difference
Sharpe ratio: Return per unit of total volatility	0.98	1.21	-0.23
Sortino ratio: Return per unit of downside risk	1.48	1.82	-0.33
Omega ratio: Gain probability vs. loss probability	1.17	1.21	-0.04
Calmar ratio: Return relative to maximum drawdown	1.19	1.63	-0.44
Martin ratio: Return relative to average drawdown	3.31	4.67	-1.36

VBILX vs. SSAFX - Sharpe Ratio Comparison

The current VBILX Sharpe Ratio is 0.98, which is comparable to the SSAFX Sharpe Ratio of 1.21. The chart below compares the historical Sharpe Ratios of VBILX and SSAFX, 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

VBILX vs. SSAFX - Drawdown Comparison

The maximum VBILX drawdown since its inception was -19.26%, roughly equal to the maximum SSAFX drawdown of -18.74%. Use the drawdown chart below to compare losses from any high point for VBILX and SSAFX.

Drawdown Indicators

	VBILX	SSAFX	Difference
Max Drawdown Largest peak-to-trough decline	-19.26%	-18.74%	-0.52%
Max Drawdown (1Y) Largest decline over 1 year	-3.43%	-2.74%	-0.69%
Max Drawdown (3Y) Largest decline over 3 years	-6.05%	-6.09%	+0.04%
Max Drawdown (5Y) Largest decline over 5 years	-19.15%	-18.10%	-1.05%
Max Drawdown (10Y) Largest decline over 10 years	-19.26%	-18.74%	-0.52%
Current Drawdown Current decline from peak	-2.31%	-2.71%	+0.40%
Average Drawdown Average peak-to-trough decline	-3.15%	-4.40%	+1.25%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.23%	0.96%	+0.27%

Volatility

VBILX vs. SSAFX - Volatility Comparison

Vanguard Intermediate-Term Bond Index Fund Admiral Shares (VBILX) has a higher volatility of 1.33% compared to State Street Aggregate Bond Index Portfolio (SSAFX) at 1.08%. This indicates that VBILX's price experiences larger fluctuations and is considered to be riskier than SSAFX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VBILX	SSAFX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.33%	1.08%	+0.25%
Volatility (6M) Calculated over the trailing 6-month period	3.12%	2.74%	+0.38%
Volatility (1Y) Calculated over the trailing 1-year period	4.15%	3.69%	+0.46%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.39%	5.95%	+0.44%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.37%	277.57%	-272.20%

VBILX vs. SSAFX - Expense Ratio Comparison

VBILX has a 0.06% expense ratio, which is higher than SSAFX's 0.02% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

VBILX vs. SSAFX - Dividend Comparison

VBILX's dividend yield for the trailing twelve months is around 4.23%, more than SSAFX's 4.17% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SSAFX State Street Aggregate Bond Index Portfolio	4.17%	3.70%	3.76%	3.16%	2.49%	1.90%	2.41%	2.88%	2.82%	2.42%	2.21%	3.21%
VBILX Vanguard Intermediate-Term Bond Index Fund Admiral Shares	4.23%	4.01%	3.80%	3.09%	1.99%	3.39%	2.94%	2.73%	2.87%	2.73%	3.06%	3.09%

Frequently Asked Questions

Can I hold both VBILX and SSAFX in my portfolio?

With a correlation of 0.92, VBILX and SSAFX 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, VBILX or SSAFX?

VBILX has higher volatility (1.33%) compared to SSAFX (1.08%). In terms of maximum drawdown, VBILX dropped -19.26% vs SSAFX's -18.74%.

Which has better risk-adjusted returns?

SSAFX currently has the higher Sharpe Ratio (1.21 vs 0.98), 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.