SPTU vs. ARB

Last updated Jun 4, 2026

SPTU (State Street SPDR Portfolio Ultra Short T-Bill ETF) and ARB (AltShares Merger Arbitrage ETF) are both exchange-traded funds - SPTU is a Ultrashort Bond fund tracking the ICE BofA US Treasury Bill Index, while ARB is a Hedge Fund fund tracking the Water Island Merger Arbitrage USD Hedged Index. Both are passively managed. At a correlation of -0.13, they often move in opposite directions. SPTU charges 0.05%/yr vs 0.87%/yr for ARB.

Performance

SPTU vs. ARB - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in State Street SPDR Portfolio Ultra Short T-Bill ETF (SPTU) and AltShares Merger Arbitrage ETF (ARB). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SPTU achieves a 1.48% return, which is significantly lower than ARB's 1.70% return.

SPTU

• 1D: 0.00%
• 1M: 0.31%
• YTD: 1.48%
• 6M: 1.81%
• 1Y: —
• 3Y*: —
• 5Y*: —
• 10Y*: —

ARB

• 1D: 0.03%
• 1M: 0.35%
• YTD: 1.70%
• 6M: 2.28%
• 1Y: 4.90%
• 3Y*: 6.40%
• 5Y*: 3.87%
• 10Y*: —

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

SPTU vs. ARB - Yearly Performance Comparison

	2026 (YTD)	2025
SPTU State Street SPDR Portfolio Ultra Short T-Bill ETF	1.48%	0.92%
ARB AltShares Merger Arbitrage ETF	1.70%	0.47%

Correlation

The correlation between SPTU and ARB is -0.13, meaning they tend to move in opposite directions. This is especially valuable for risk management - when one declines, the other has historically tended to hold steady or rise.

	Correlation
Correlation (All Time) Calculated using the full available price history since Oct 9, 2025	-0.13

Return for Risk

SPTU vs. ARB — Risk / Return Rank

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

ARB

ARB Risk / Return Rank: 69
ARB Sharpe Ratio Rank: 48
ARB Sortino Ratio Rank: 57
ARB Omega Ratio Rank: 56
ARB Calmar Ratio Rank: 94
ARB Martin Ratio Rank: 90

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.

SPTU vs. ARB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for State Street SPDR Portfolio Ultra Short T-Bill ETF (SPTU) and AltShares Merger Arbitrage ETF (ARB). 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.

Risk / return metrics aren't available yet — we need at least 12 months of trading data to calculate them.

Sharpe Ratios by Period

	SPTU	ARB	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	—	1.70	—
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	—	0.88	—
Sharpe Ratio (All Time) Calculated using the full available price history	11.82	0.95	+10.87

Drawdowns

SPTU vs. ARB - Drawdown Comparison

The maximum SPTU drawdown since its inception was -0.04%, smaller than the maximum ARB drawdown of -5.60%. Use the drawdown chart below to compare losses from any high point for SPTU and ARB.

Drawdown Indicators

	SPTU	ARB	Difference
Max Drawdown Largest peak-to-trough decline	-0.04%	-5.60%	+5.56%
Max Drawdown (1Y) Largest decline over 1 year	—	-0.69%	—
Max Drawdown (3Y) Largest decline over 3 years	—	-2.13%	—
Max Drawdown (5Y) Largest decline over 5 years	—	-5.60%	—
Current Drawdown Current decline from peak	0.00%	-0.49%	+0.49%
Average Drawdown Average peak-to-trough decline	-0.00%	-0.94%	+0.94%
Ulcer Index Depth and duration of drawdowns from previous peaks	—	0.24%	—

Volatility

Volatility by Period

	SPTU	ARB	Difference
Volatility (1M) Calculated over the trailing 1-month period	—	1.28%	—
Volatility (6M) Calculated over the trailing 6-month period	—	2.38%	—
Volatility (1Y) Calculated over the trailing 1-year period	0.32%	2.89%	-2.57%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	0.32%	4.40%	-4.08%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	0.32%	4.40%	-4.08%

SPTU vs. ARB - Expense Ratio Comparison

SPTU has a 0.05% expense ratio, which is lower than ARB's 0.87% expense ratio.

Dividends

SPTU vs. ARB - Dividend Comparison

SPTU's dividend yield for the trailing twelve months is around 2.36%, more than ARB's 0.43% yield.

Position	TTM	2025	2024	2023	2022	2021	2020
ARB AltShares Merger Arbitrage ETF	0.43%	0.43%	1.12%	0.00%	4.18%	0.00%	2.87%
SPTU State Street SPDR Portfolio Ultra Short T-Bill ETF	2.36%	0.89%	0.00%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both SPTU and ARB in my portfolio?

SPTU and ARB have a correlation of -0.13, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which ETF is better, SPTU or ARB?

On fees, SPTU is cheaper at 0.05% per year. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF is cheaper, SPTU or ARB?

SPTU is cheaper with a 0.05% expense ratio, compared with 0.87% for ARB.

Which ETF pays a higher dividend yield, SPTU or ARB?

SPTU has the higher dividend yield at 2.36%, compared with 0.43% for ARB.

What is the main difference between SPTU and ARB?

SPTU is categorized as Ultrashort Bond, while ARB is Hedge Fund. SPTU tracks ICE BofA US Treasury Bill Index, while ARB tracks Water Island Merger Arbitrage USD Hedged Index. They also come from different issuers: State Street and Water Island Capital Partners LP. Their fees differ too: 0.05% for SPTU and 0.87% for ARB.