The SPDR Bloomberg 1–3 Month T-Bill ETF (BIL) is designed for investors seeking exposure to short-term U.S. Treasury securities while maintaining a high level of capital preservation and liquidity. As interest rates remain a key consideration for cash management and fixed-income strategies, BIL has become a popular choice among investors looking for a low-risk alternative to traditional cash holdings and money market instruments.
This article provides a detailed overview of the SPDR Bloomberg 1–3 Month T-Bill ETF, including its investment objective, portfolio characteristics, performance, risks, and suitability for different types of investors.
What Is the SPDR Bloomberg 1–3 Month T-Bill ETF (BIL)?
The SPDR Bloomberg 1–3 Month T-Bill ETF seeks to deliver investment results that correspond, before fees and expenses, to the performance of the Bloomberg 1–3 Month U.S. Treasury Bill Index.
The fund invests primarily in publicly issued U.S. Treasury Bills with remaining maturities ranging from one month to less than three months. Because Treasury Bills are backed by the full faith and credit of the U.S. government, they are generally considered among the safest fixed-income investments available.
Key Features
- Provides exposure to short-term U.S. Treasury Bills.
- Focuses on securities with maturities between one and three months.
- Offers lower interest-rate sensitivity than longer-duration bonds.
- Rebalanced monthly to maintain index alignment.
- Trades on stock exchanges like a standard equity ETF.
Fund Overview
| Metric | Value |
|---|---|
| Fund Name | SPDR Bloomberg 1–3 Month T-Bill ETF |
| Ticker | BIL |
| Exchange | NYSE Arca |
| Inception Date | May 25, 2007 |
| Benchmark | Bloomberg 1–3 Month U.S. Treasury Bill Index |
| Base Currency | USD |
| Distribution Frequency | Monthly |
| Gross Expense Ratio | 0.1353% |
| Assets Under Management | $46.74 Billion |
| Net Asset Value (NAV) | $91.59 |
The ETF has accumulated significant assets under management, reflecting strong investor demand for short-duration Treasury exposure and cash-management solutions.
Understanding the Benchmark Index
The Bloomberg 1–3 Month U.S. Treasury Bill Index measures the performance of investment-grade Treasury Bills issued by the U.S. government with remaining maturities between one and three months.
To qualify for inclusion, securities must:
- Be publicly issued U.S. Treasury obligations.
- Have a maturity of at least one month and less than three months.
- Be denominated in U.S. dollars.
- Carry fixed-rate structures.
- Meet investment-grade quality standards.
The index is market-capitalization weighted, making it representative of the short-term Treasury market.
Portfolio Characteristics
One of the defining features of BIL is its exceptionally short duration profile.
Portfolio Statistics
| Characteristic | Value |
|---|---|
| Number of Holdings | 34 |
| Average Maturity | 0.09 Years |
| Option-Adjusted Duration | 0.09 Years |
| Average Price | $99.60 |
| Yield to Maturity | 3.65% |
| Average Yield to Worst | 3.65% |
Because the average maturity is approximately one month, the fund is minimally affected by changes in interest rates compared with intermediate- or long-term bond funds.
Credit Quality
The portfolio is invested almost entirely in U.S. Treasury securities.
| Credit Quality | Weight |
|---|---|
| AA1 | 99.92% |
| AAA / Cash | 0.08% |
This high-quality allocation contributes to the ETF’s reputation as a low-risk fixed-income vehicle.
Sector Allocation
BIL maintains a highly concentrated sector exposure due to its investment mandate.
| Sector | Weight |
|---|---|
| Treasury Securities | 99.92% |
| Cash | 0.08% |
Unlike diversified bond funds, the ETF does not allocate assets to corporate bonds, municipal debt, mortgage-backed securities, or other credit-sensitive sectors.
Top Holdings
The ETF primarily holds recently issued U.S. Treasury Bills scheduled to mature within weeks.
Some of the largest positions include Treasury Bills maturing in July and August 2026, with individual allocations ranging from approximately 6% to 12% of the portfolio.
This structure ensures:
- High liquidity.
- Frequent reinvestment opportunities.
- Reduced interest-rate risk.
- Strong alignment with prevailing short-term Treasury yields.
Yield and Income Potential
Investors often use BIL as an income-generating cash alternative.
Yield Metrics
| Yield Measure | Value |
|---|---|
| 30-Day SEC Yield | 3.50% |
| Fund Distribution Yield | 3.85% |
| Yield to Maturity | 3.65% |
Because the fund continuously replaces maturing Treasury Bills with newly issued securities, its yield tends to adjust relatively quickly when short-term interest rates change.
For investors seeking current income while preserving principal, these yield levels can be attractive compared with traditional bank savings accounts, depending on prevailing market conditions.
Historical Performance
Performance as of May 31, 2026
| Period | Fund NAV Return |
|---|---|
| 1 Month | 0.30% |
| Quarter-to-Date | 0.59% |
| Year-to-Date | 1.44% |
| 1 Year | 3.87% |
| 3 Years (Annualized) | 4.65% |
| 5 Years (Annualized) | 3.40% |
| 10 Years (Annualized) | 2.18% |
| Since Inception | 1.36% |
The ETF has closely tracked its benchmark index, which is expected for a passive index-tracking strategy.
Important Performance Considerations
Investors should remember that:
- Past performance does not guarantee future results.
- Future yields depend heavily on Federal Reserve policy and short-term interest rates.
- ETF market prices may fluctuate slightly around net asset value.
- Returns may vary depending on purchase and sale timing.
Trading Characteristics
Like stocks, ETF shares can be bought and sold throughout the trading day.
Market Data
| Metric | Value |
|---|---|
| Closing Price | $91.59 |
| Bid/Ask Midpoint | $91.60 |
| Premium/Discount to NAV | 0.00% |
| 30-Day Median Bid/Ask Spread | 0.01% |
| Daily Trading Volume | 417,226 Shares |
The narrow bid-ask spread demonstrates strong liquidity and efficient trading conditions.
Premiums and Discounts
Although ETFs generally trade close to NAV, small premiums or discounts can occur.
Recent trading statistics show:
| Period | Days at Premium | Days at Discount |
|---|---|---|
| Calendar Year 2025 | 159 | 91 |
| First Quarter 2026 | 41 | 20 |
Investors should be aware that ETF shares may occasionally trade above or below the value of underlying holdings.
Benefits of Investing in BIL
Capital Preservation
Because the ETF invests in short-term Treasury Bills, principal volatility is typically low compared with longer-duration bond funds.
Liquidity
Shares can be traded throughout the day, making BIL a flexible cash-management tool.
Interest Rate Resilience
The extremely short duration reduces sensitivity to changes in interest rates.
Government Backing
Treasury Bills are backed by the U.S. government, making credit risk relatively low.
Monthly Income Distribution
The ETF distributes income monthly, providing regular cash flow for investors.
Risks to Consider
While BIL is generally viewed as a conservative investment, it is not risk-free.
Interest Rate Risk
Although limited, changes in short-term rates can influence yield and total return.
Inflation Risk
If inflation exceeds the fund’s yield, investors may experience a decline in real purchasing power.
Market Trading Risk
ETF shares can trade at slight premiums or discounts to NAV.
Income Fluctuation
Future distributions will vary as Treasury Bill yields change over time.
Who May Consider the SPDR Bloomberg 1–3 Month T-Bill ETF?
BIL may be appropriate for:
- Conservative investors seeking capital preservation.
- Individuals maintaining emergency funds.
- Investors waiting for opportunities in equities or longer-duration bonds.
- Institutions managing short-term cash balances.
- Retirees looking for lower-volatility income solutions.
It may be less suitable for investors seeking long-term capital appreciation or higher income levels available from riskier asset classes.
Internal Resources
For further research, consider exploring:
- Understanding Treasury Bills and short-term government securities
- Comparing Treasury ETFs versus money market funds
- Building a defensive fixed-income portfolio
- Managing cash during volatile market conditions
- Strategies for rising and falling interest-rate environments
Conclusion
The SPDR Bloomberg 1–3 Month T-Bill ETF (BIL) provides investors with efficient access to a diversified portfolio of short-term U.S. Treasury Bills. Its combination of liquidity, low duration, government-backed holdings, and competitive short-term yields makes it a compelling option for cash management and capital preservation strategies.
While the fund is not immune to market and interest-rate risks, its conservative profile and strong alignment with short-term Treasury markets make it a valuable tool for investors seeking stability in uncertain environments. Before investing, evaluate your financial objectives, risk tolerance, and income needs, and consider reviewing the fund’s prospectus and related investment materials.
For additional insights, explore our guides on Treasury investing, fixed-income ETFs, portfolio diversification, and cash-management strategies.
References
- State Street Global Advisors. SPDR Bloomberg 1–3 Month T-Bill ETF (BIL) Fund Information.
- Bloomberg Index Services Limited. Bloomberg 1–3 Month U.S. Treasury Bill Index Methodology.
- U.S. Department of the Treasury. Treasury Bills and Government Securities Information.
- U.S. Securities and Exchange Commission (SEC). ETF Investor Education Resources.
- Federal Reserve System. Short-Term Interest Rate and Treasury Market Data.