BBSOX vs. PRTBX

Last updated Jun 4, 2026

BBSOX (BlackRock Short Obligations Fund) and PRTBX (Permanent Portfolio Short-Term Treasury Portfolio) are both Ultrashort Bond funds. Over the past 10 years, BBSOX returned 2.48%/yr vs 1.26%/yr for PRTBX. At a 0.24 correlation, their price movements are largely independent. BBSOX charges 0.30%/yr vs 0.65%/yr for PRTBX.

Performance

BBSOX vs. PRTBX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in BlackRock Short Obligations Fund (BBSOX) and Permanent Portfolio Short-Term Treasury Portfolio (PRTBX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BBSOX achieves a 1.49% return, which is significantly higher than PRTBX's 0.76% return. Over the past 10 years, BBSOX has outperformed PRTBX with an annualized return of 2.48%, while PRTBX has yielded a comparatively lower 1.26% annualized return.

BBSOX

• 1D: 0.00%
• 1M: 0.34%
• YTD: 1.49%
• 6M: 1.85%
• 1Y: 4.24%
• 3Y*: 4.77%
• 5Y*: 3.27%
• 10Y*: 2.48%

PRTBX

• 1D: 0.00%
• 1M: 0.18%
• YTD: 0.76%
• 6M: 1.03%
• 1Y: 3.18%
• 3Y*: 3.85%
• 5Y*: 1.98%
• 10Y*: 1.26%

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

BBSOX vs. PRTBX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BBSOX BlackRock Short Obligations Fund	1.49%	4.74%	5.36%	4.36%	0.60%	-0.10%	1.54%	3.01%	1.96%	1.18%
PRTBX Permanent Portfolio Short-Term Treasury Portfolio	0.76%	4.19%	4.12%	3.79%	-2.28%	-0.74%	0.10%	1.76%	1.16%	0.12%

Correlation

The correlation between BBSOX and PRTBX is 0.37, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.37
Correlation (3Y) Calculated over the trailing 3-year period	0.42
Correlation (5Y) Calculated over the trailing 5-year period	0.41
Correlation (10Y) Calculated over the trailing 10-year period	0.28
Correlation (All Time) Calculated using the full available price history since Jan 3, 2013	0.24

The correlation between BBSOX and PRTBX shifts across timeframes, from 0.24 (all time) to 0.42 (3 years), reflecting how their relationship changes across market environments.

Return for Risk

BBSOX vs. PRTBX — Risk / Return Rank

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

BBSOX

BBSOX Risk / Return Rank: 98
BBSOX Sharpe Ratio Rank: 93
BBSOX Sortino Ratio Rank: 100
BBSOX Omega Ratio Rank: 99
BBSOX Calmar Ratio Rank: 100
BBSOX Martin Ratio Rank: 99

PRTBX

PRTBX Risk / Return Rank: 99
PRTBX Sharpe Ratio Rank: 99
PRTBX Sortino Ratio Rank: 99
PRTBX Omega Ratio Rank: 98
PRTBX Calmar Ratio Rank: 99
PRTBX Martin Ratio Rank: 99

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.

BBSOX vs. PRTBX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for BlackRock Short Obligations Fund (BBSOX) and Permanent Portfolio Short-Term Treasury Portfolio (PRTBX). 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.

	BBSOX	PRTBX	Difference
Sharpe ratio: Return per unit of total volatility	3.20	4.73	-1.53
Sortino ratio: Return per unit of downside risk	11.68	8.82	+2.86
Omega ratio: Gain probability vs. loss probability	4.23	2.27	+1.96
Calmar ratio: Return relative to maximum drawdown	21.50	10.02	+11.48
Martin ratio: Return relative to average drawdown	70.26	48.61	+21.65
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

BBSOX vs. PRTBX - Sharpe Ratio Comparison

The current BBSOX Sharpe Ratio is 3.20, which is lower than the PRTBX Sharpe Ratio of 4.73. The chart below compares the historical Sharpe Ratios of BBSOX and PRTBX, 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

	BBSOX	PRTBX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.20	4.73	-1.53
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	2.63	1.65	+0.98
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	2.42	1.46	+0.96
Sharpe Ratio (All Time) Calculated using the full available price history	2.24	3.89	-1.66

Drawdowns

BBSOX vs. PRTBX - Drawdown Comparison

The maximum BBSOX drawdown since its inception was -1.59%, smaller than the maximum PRTBX drawdown of -5.13%. Use the drawdown chart below to compare losses from any high point for BBSOX and PRTBX.

Drawdown Indicators

	BBSOX	PRTBX	Difference
Max Drawdown Largest peak-to-trough decline	-1.59%	-5.13%	+3.54%
Max Drawdown (1Y) Largest decline over 1 year	-0.20%	-0.32%	+0.12%
Max Drawdown (3Y) Largest decline over 3 years	-0.30%	-0.44%	+0.14%
Max Drawdown (5Y) Largest decline over 5 years	-1.00%	-3.70%	+2.70%
Max Drawdown (10Y) Largest decline over 10 years	-1.59%	-4.36%	+2.77%
Current Drawdown Current decline from peak	0.00%	-0.02%	+0.02%
Average Drawdown Average peak-to-trough decline	-0.08%	-0.96%	+0.88%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.06%	0.07%	-0.01%

Volatility

BBSOX vs. PRTBX - Volatility Comparison

BlackRock Short Obligations Fund (BBSOX) has a higher volatility of 0.40% compared to Permanent Portfolio Short-Term Treasury Portfolio (PRTBX) at 0.15%. This indicates that BBSOX's price experiences larger fluctuations and is considered to be riskier than PRTBX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BBSOX	PRTBX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.40%	0.15%	+0.25%
Volatility (6M) Calculated over the trailing 6-month period	0.88%	0.40%	+0.48%
Volatility (1Y) Calculated over the trailing 1-year period	1.33%	0.68%	+0.65%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	1.25%	1.21%	+0.04%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	1.03%	0.86%	+0.17%

BBSOX vs. PRTBX - Expense Ratio Comparison

BBSOX has a 0.30% expense ratio, which is lower than PRTBX's 0.65% expense ratio.

Dividends

BBSOX vs. PRTBX - Dividend Comparison

BBSOX's dividend yield for the trailing twelve months is around 4.25%, more than PRTBX's 3.36% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BBSOX BlackRock Short Obligations Fund	4.25%	4.43%	5.01%	3.35%	1.29%	0.30%	1.13%	2.56%	2.24%	1.17%	1.03%	0.62%
PRTBX Permanent Portfolio Short-Term Treasury Portfolio	3.36%	3.39%	2.69%	1.79%	0.00%	0.00%	0.21%	1.65%	0.83%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both BBSOX and PRTBX in my portfolio?

BBSOX and PRTBX have a correlation of 0.37, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, BBSOX or PRTBX?

BBSOX has higher volatility (0.40%) compared to PRTBX (0.15%). In terms of maximum drawdown, BBSOX dropped -1.59% vs PRTBX's -5.13%.

Which has better risk-adjusted returns?

PRTBX currently has the higher Sharpe Ratio (4.72 vs 3.20), 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.