BILS vs. SPY
BILS (SPDR Bloomberg 3-12 Month T-Bill ETF) and SPY (State Street SPDR S&P 500 ETF) are both exchange-traded funds - BILS is a Ultrashort Bond fund tracking the Bloomberg 3-12 Month U.S. Treasury Bill Index, while SPY is a S&P 500 fund tracking the S&P 500 Index. Both are passively managed. Over the past 5 years, BILS returned 3.33%/yr vs 13.51%/yr for SPY. At a correlation of -0.01, they often move in opposite directions. BILS charges 0.14%/yr vs 0.09%/yr for SPY.
Performance
BILS vs. SPY - Performance Comparison
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Returns By Period
In the year-to-date period, BILS achieves a 1.57% return, which is significantly lower than SPY's 9.74% return.
BILS
- 1D
- 0.01%
- 1M
- 0.24%
- YTD
- 1.57%
- 6M
- 1.67%
- 1Y
- 3.86%
- 3Y*
- 4.61%
- 5Y*
- 3.33%
- 10Y*
- —
SPY
- 1D
- -0.31%
- 1M
- 0.09%
- YTD
- 9.74%
- 6M
- 9.27%
- 1Y
- 26.65%
- 3Y*
- 21.27%
- 5Y*
- 13.51%
- 10Y*
- 15.70%
BILS vs. SPY - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | |
|---|---|---|---|---|---|---|---|
BILS SPDR Bloomberg 3-12 Month T-Bill ETF | 1.57% | 4.23% | 5.17% | 4.92% | 0.90% | -0.08% | -0.01% |
SPY State Street SPDR S&P 500 ETF | 9.74% | 17.72% | 24.89% | 26.18% | -18.18% | 28.73% | 16.38% |
Correlation
The correlation between BILS and SPY is 0.07, meaning there is essentially no relationship between their price movements. Each responds to its own set of market drivers, making them strong candidates for combining in a diversified portfolio.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.07 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.01 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.01 |
Correlation (All Time) Calculated using the full available price history since Sep 24, 2020 | -0.01 |
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Return for Risk
BILS vs. SPY — Risk / Return Rank
BILS
SPY
BILS vs. SPY - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for SPDR Bloomberg 3-12 Month T-Bill ETF (BILS) and State Street SPDR S&P 500 ETF (SPY). 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.
| BILS | SPY | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +14.61 | ||
| Sortino ratioReturn per unit of downside risk | +85.25 | ||
| Omega ratioGain probability vs. loss probability | 34.42 | 1.39 | +33.03 |
| Calmar ratioReturn relative to maximum drawdown | 128.51 | 3.01 | +125.50 |
| Martin ratioReturn relative to average drawdown | 1,292.26 | 13.54 | +1,278.73 |
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Drawdowns
BILS vs. SPY - Drawdown Comparison
The maximum BILS drawdown since its inception was -0.41%, smaller than the maximum SPY drawdown of -55.19%. Use the drawdown chart below to compare losses from any high point for BILS and SPY.
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Drawdown Indicators
| BILS | SPY | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -0.41% | -55.19% | +54.78% |
Max Drawdown (1Y)Largest decline over 1 year | -0.03% | -8.88% | +8.85% |
Max Drawdown (3Y)Largest decline over 3 years | -0.04% | -18.76% | +18.72% |
Max Drawdown (5Y)Largest decline over 5 years | -0.37% | -24.50% | +24.13% |
Max Drawdown (10Y)Largest decline over 10 years | — | -33.72% | — |
Current DrawdownCurrent decline from peak | 0.00% | -1.75% | +1.75% |
Average DrawdownAverage peak-to-trough decline | -0.04% | -9.04% | +9.00% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.00% | 1.97% | -1.97% |
Volatility
BILS vs. SPY - Volatility Comparison
The current volatility for SPDR Bloomberg 3-12 Month T-Bill ETF (BILS) is 0.06%, while State Street SPDR S&P 500 ETF (SPY) has a volatility of 4.64%. This indicates that BILS experiences smaller price fluctuations and is considered to be less risky than SPY based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| BILS | SPY | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 0.06% | 4.64% | -4.58% |
Volatility (6M)Calculated over the trailing 6-month period | 0.14% | 9.75% | -9.61% |
Volatility (1Y)Calculated over the trailing 1-year period | 0.23% | 12.43% | -12.20% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 0.31% | 17.14% | -16.83% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 0.30% | 17.99% | -17.69% |
BILS vs. SPY - Expense Ratio Comparison
BILS has a 0.14% expense ratio, which is higher than SPY's 0.09% 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
BILS vs. SPY - Dividend Comparison
BILS's dividend yield for the trailing twelve months is around 3.81%, more than SPY's 1.01% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
BILS SPDR Bloomberg 3-12 Month T-Bill ETF | 3.81% | 4.08% | 5.01% | 4.98% | 1.61% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% |
SPY State Street SPDR S&P 500 ETF | 1.01% | 1.07% | 1.21% | 1.40% | 1.65% | 1.20% | 1.52% | 1.75% | 2.04% | 1.80% | 2.03% | 2.06% |
Frequently Asked Questions
BILS and SPY have a correlation of 0.07, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.
SPY has higher volatility (4.64%) compared to BILS (0.06%). In terms of maximum drawdown, BILS dropped -0.41% vs SPY's -55.19%.
On 5-year performance, SPY leads with 13.51% vs 3.33% for BILS. On fees, SPY is cheaper at 0.09% per year. On volatility, BILS has been the lower-risk option at 0.06%. The better choice depends on whether you care most about return, fees, risk, or income.
Over the 5-year period, SPY has performed better with a 13.51% return vs 3.33%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.
SPY is cheaper with a 0.09% expense ratio, compared with 0.14% for BILS.
BILS has the higher dividend yield at 3.81%, compared with 1.01% for SPY.
BILS is categorized as Ultrashort Bond, while SPY is S&P 500. BILS tracks Bloomberg 3-12 Month U.S. Treasury Bill Index, while SPY tracks S&P 500 Index. Their fees differ too: 0.14% for BILS and 0.09% for SPY.
BILS currently has the higher Sharpe Ratio (16.76 vs 2.16), 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.
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