SSFDX vs. OWFIX

Last updated Jun 3, 2026

SSFDX (State Street Aggregate Bond Index Fund) and OWFIX (Old Westbury Fixed Income Fund) are both Intermediate Core Bond funds. Over the past 10 years, SSFDX returned -19.41%/yr vs 1.69%/yr for OWFIX. Their correlation of 0.89 suggests significant overlap in exposure. SSFDX charges 0.23%/yr vs 0.57%/yr for OWFIX.

Performance

SSFDX vs. OWFIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in State Street Aggregate Bond Index Fund (SSFDX) and Old Westbury Fixed Income Fund (OWFIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

Over the past 10 years, SSFDX has underperformed OWFIX with an annualized return of -19.41%, while OWFIX has yielded a comparatively higher 1.69% annualized return.

SSFDX

• 1D: -0.08%
• 1M: 0.11%
• YTD: 0.37%
• 6M: 0.41%
• 1Y: 5.31%
• 3Y*: 3.84%
• 5Y*: -0.04%
• 10Y*: -19.41%

OWFIX

• 1D: -0.10%
• 1M: -0.10%
• YTD: -0.00%
• 6M: 0.06%
• 1Y: 3.71%
• 3Y*: 4.04%
• 5Y*: 0.89%
• 10Y*: 1.69%

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

SSFDX vs. OWFIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SSFDX State Street Aggregate Bond Index Fund	0.37%	6.80%	1.36%	5.39%	-13.36%	-1.98%	-89.24%	8.98%	-0.20%	3.29%
OWFIX Old Westbury Fixed Income Fund	-0.00%	7.48%	1.93%	4.81%	-8.39%	-1.87%	7.41%	6.12%	0.64%	1.41%

Correlation

The correlation between SSFDX and OWFIX is 0.82, 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	0.82
Correlation (3Y) Calculated over the trailing 3-year period	0.88
Correlation (5Y) Calculated over the trailing 5-year period	0.90
Correlation (10Y) Calculated over the trailing 10-year period	0.89
Correlation (All Time) Calculated using the full available price history since Sep 23, 2014	0.89

The correlation between SSFDX and OWFIX has been stable across timeframes, ranging from 0.82 to 0.90 - a consistent structural relationship.

Return for Risk

SSFDX vs. OWFIX — Risk / Return Rank

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

SSFDX

SSFDX Risk / Return Rank: 22
SSFDX Sharpe Ratio Rank: 22
SSFDX Sortino Ratio Rank: 23
SSFDX Omega Ratio Rank: 20
SSFDX Calmar Ratio Rank: 26
SSFDX Martin Ratio Rank: 22

OWFIX

OWFIX Risk / Return Rank: 24
OWFIX Sharpe Ratio Rank: 23
OWFIX Sortino Ratio Rank: 26
OWFIX Omega Ratio Rank: 23
OWFIX Calmar Ratio Rank: 26
OWFIX Martin Ratio Rank: 21

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.

SSFDX vs. OWFIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for State Street Aggregate Bond Index Fund (SSFDX) and Old Westbury Fixed Income Fund (OWFIX). 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.

	SSFDX	OWFIX	Difference
Sharpe ratio Return per unit of total volatility	1.35	1.39	-0.04
Sortino ratio Return per unit of downside risk	2.02	2.13	-0.12
Omega ratio Gain probability vs. loss probability	1.24	1.25	-0.01
Calmar ratio Return relative to maximum drawdown	1.90	1.94	-0.04
Martin ratio Return relative to average drawdown	5.85	5.60	+0.26
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

SSFDX vs. OWFIX - Sharpe Ratio Comparison

The current SSFDX Sharpe Ratio is 1.35, which is comparable to the OWFIX Sharpe Ratio of 1.39. The chart below compares the historical Sharpe Ratios of SSFDX and OWFIX, 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

	SSFDX	OWFIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.35	1.39	-0.04
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	-0.01	0.21	-0.22
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	-0.61	0.48	-1.10
Sharpe Ratio (All Time) Calculated using the full available price history	-0.56	0.88	-1.43

Drawdowns

SSFDX vs. OWFIX - Drawdown Comparison

The maximum SSFDX drawdown since its inception was -92.69%, which is greater than OWFIX's maximum drawdown of -12.88%. Use the drawdown chart below to compare losses from any high point for SSFDX and OWFIX.

Drawdown Indicators

	SSFDX	OWFIX	Difference
Max Drawdown Largest peak-to-trough decline	-92.69%	-12.88%	-79.81%
Max Drawdown (1Y) Largest decline over 1 year	-2.75%	-2.23%	-0.52%
Max Drawdown (3Y) Largest decline over 3 years	-6.13%	-3.78%	-2.35%
Max Drawdown (5Y) Largest decline over 5 years	-18.19%	-12.40%	-5.79%
Max Drawdown (10Y) Largest decline over 10 years	-92.69%	-12.88%	-79.81%
Current Drawdown Current decline from peak	-90.13%	-1.35%	-88.78%
Average Drawdown Average peak-to-trough decline	-48.02%	-2.25%	-45.77%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.90%	0.77%	+0.13%

Volatility

SSFDX vs. OWFIX - Volatility Comparison

State Street Aggregate Bond Index Fund (SSFDX) has a higher volatility of 1.30% compared to Old Westbury Fixed Income Fund (OWFIX) at 0.83%. This indicates that SSFDX's price experiences larger fluctuations and is considered to be riskier than OWFIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SSFDX	OWFIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.30%	0.83%	+0.47%
Volatility (6M) Calculated over the trailing 6-month period	2.66%	2.05%	+0.61%
Volatility (1Y) Calculated over the trailing 1-year period	3.75%	3.12%	+0.63%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.93%	4.40%	+1.53%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	31.82%	3.55%	+28.27%

SSFDX vs. OWFIX - Expense Ratio Comparison

SSFDX has a 0.23% expense ratio, which is lower than OWFIX's 0.57% expense ratio.

Dividends

SSFDX vs. OWFIX - Dividend Comparison

SSFDX's dividend yield for the trailing twelve months is around 4.06%, more than OWFIX's 3.77% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
OWFIX Old Westbury Fixed Income Fund	3.77%	4.72%	3.95%	3.08%	2.06%	1.91%	5.05%	1.88%	1.90%	1.49%	1.33%	1.31%
SSFDX State Street Aggregate Bond Index Fund	4.06%	3.64%	3.59%	2.95%	2.27%	3.12%	8.84%	3.15%	2.79%	2.43%	2.19%	4.63%

Frequently Asked Questions

Can I hold both SSFDX and OWFIX in my portfolio?

SSFDX and OWFIX have a correlation of 0.82, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SSFDX or OWFIX?

SSFDX has higher volatility (1.30%) compared to OWFIX (0.83%). In terms of maximum drawdown, SSFDX dropped -92.69% vs OWFIX's -12.88%.

Which has better risk-adjusted returns?

OWFIX currently has the higher Sharpe Ratio (1.39 vs 1.35), 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.