PAIPX vs. MUIIX

Last updated Jun 4, 2026

PAIPX (PIMCO Short Asset Investment Fund) and MUIIX (Morgan Stanley Institutional Fund Trust Ultra-Short Income Portfolio) are both Ultrashort Bond funds. Over the past 5 years, PAIPX returned 3.36%/yr vs 3.25%/yr for MUIIX. At a 0.39 correlation, their price movements are largely independent. PAIPX charges 0.45%/yr vs 0.35%/yr for MUIIX.

Performance

PAIPX vs. MUIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in PIMCO Short Asset Investment Fund (PAIPX) and Morgan Stanley Institutional Fund Trust Ultra-Short Income Portfolio (MUIIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PAIPX achieves a 1.80% return, which is significantly higher than MUIIX's 1.57% return.

PAIPX

• 1D: 0.00%
• 1M: 0.41%
• YTD: 1.80%
• 6M: 2.25%
• 1Y: 4.65%
• 3Y*: 5.16%
• 5Y*: 3.36%
• 10Y*: 2.51%

MUIIX

• 1D: 0.00%
• 1M: 0.32%
• YTD: 1.57%
• 6M: 1.91%
• 1Y: 4.22%
• 3Y*: 4.41%
• 5Y*: 3.25%
• 10Y*: —

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

PAIPX vs. MUIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020
PAIPX PIMCO Short Asset Investment Fund	1.80%	4.83%	5.93%	4.55%	-0.00%	-0.19%	2.72%
MUIIX Morgan Stanley Institutional Fund Trust Ultra-Short Income Portfolio	1.57%	4.47%	4.94%	4.17%	1.10%	0.10%	0.49%

Correlation

The correlation between PAIPX and MUIIX is 0.59, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.59
Correlation (3Y) Calculated over the trailing 3-year period	0.46
Correlation (5Y) Calculated over the trailing 5-year period	0.38
Correlation (All Time) Calculated using the full available price history since Apr 8, 2020	0.39

Over the past year, PAIPX and MUIIX have become more correlated (0.59) than their long-term average of 0.39, meaning their price movements have been converging.

Return for Risk

PAIPX vs. MUIIX — Risk / Return Rank

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

PAIPX

PAIPX Risk / Return Rank: 100
PAIPX Sharpe Ratio Rank: 98
PAIPX Sortino Ratio Rank: 100
PAIPX Omega Ratio Rank: 100
PAIPX Calmar Ratio Rank: 100
PAIPX Martin Ratio Rank: 100

MUIIX

MUIIX Risk / Return Rank: 99
MUIIX Sharpe Ratio Rank: 97
MUIIX Sortino Ratio Rank: 100
MUIIX Omega Ratio Rank: 100
MUIIX Calmar Ratio Rank: 100
MUIIX Martin Ratio Rank: 100

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.

PAIPX vs. MUIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for PIMCO Short Asset Investment Fund (PAIPX) and Morgan Stanley Institutional Fund Trust Ultra-Short Income Portfolio (MUIIX). 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.

	PAIPX	MUIIX	Difference
Sharpe ratio: Return per unit of total volatility	3.93	3.61	+0.32
Sortino ratio: Return per unit of downside risk	26.36	23.95	+2.40
Omega ratio: Gain probability vs. loss probability	16.16	14.80	+1.35
Calmar ratio: Return relative to maximum drawdown	46.81	42.37	+4.43
Martin ratio: Return relative to average drawdown	185.02	126.87	+58.16
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PAIPX vs. MUIIX - Sharpe Ratio Comparison

The current PAIPX Sharpe Ratio is 3.93, which is comparable to the MUIIX Sharpe Ratio of 3.61. The chart below compares the historical Sharpe Ratios of PAIPX and MUIIX, 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

	PAIPX	MUIIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.93	3.61	+0.32
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	2.02	2.05	-0.03
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	1.87	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	1.75	1.90	-0.15

Drawdowns

PAIPX vs. MUIIX - Drawdown Comparison

The maximum PAIPX drawdown since its inception was -3.49%, which is greater than MUIIX's maximum drawdown of -1.20%. Use the drawdown chart below to compare losses from any high point for PAIPX and MUIIX.

Drawdown Indicators

	PAIPX	MUIIX	Difference
Max Drawdown Largest peak-to-trough decline	-3.49%	-1.20%	-2.29%
Max Drawdown (1Y) Largest decline over 1 year	-0.10%	-0.10%	0.00%
Max Drawdown (3Y) Largest decline over 3 years	-1.20%	-1.20%	0.00%
Max Drawdown (5Y) Largest decline over 5 years	-1.64%	-1.20%	-0.44%
Max Drawdown (10Y) Largest decline over 10 years	-3.49%	—	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-0.15%	-0.06%	-0.09%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.03%	0.03%	0.00%

Volatility

PAIPX vs. MUIIX - Volatility Comparison

The current volatility for PIMCO Short Asset Investment Fund (PAIPX) is 0.32%, while Morgan Stanley Institutional Fund Trust Ultra-Short Income Portfolio (MUIIX) has a volatility of 0.35%. This indicates that PAIPX experiences smaller price fluctuations and is considered to be less risky than MUIIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PAIPX	MUIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.32%	0.35%	-0.03%
Volatility (6M) Calculated over the trailing 6-month period	0.85%	0.78%	+0.07%
Volatility (1Y) Calculated over the trailing 1-year period	1.19%	1.17%	+0.02%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	1.67%	1.59%	+0.08%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	1.35%	1.44%	-0.09%

PAIPX vs. MUIIX - Expense Ratio Comparison

PAIPX has a 0.45% expense ratio, which is higher than MUIIX's 0.35% expense ratio.

Dividends

PAIPX vs. MUIIX - Dividend Comparison

PAIPX's dividend yield for the trailing twelve months is around 3.93%, less than MUIIX's 4.03% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MUIIX Morgan Stanley Institutional Fund Trust Ultra-Short Income Portfolio	4.03%	4.36%	4.81%	3.88%	1.20%	0.10%	0.39%	0.00%	0.00%	0.00%	0.00%	0.00%
PAIPX PIMCO Short Asset Investment Fund	3.93%	4.29%	5.04%	4.04%	1.21%	0.31%	1.00%	2.53%	2.28%	1.81%	1.21%	0.78%

Frequently Asked Questions

Can I hold both PAIPX and MUIIX in my portfolio?

PAIPX and MUIIX have a correlation of 0.59, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, PAIPX or MUIIX?

MUIIX has higher volatility (0.35%) compared to PAIPX (0.32%). In terms of maximum drawdown, PAIPX dropped -3.49% vs MUIIX's -1.20%.

Which has better risk-adjusted returns?

PAIPX currently has the higher Sharpe Ratio (3.93 vs 3.61), 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.