BIL Butterfly Strategy
BIL (State Street SPDR Bloomberg 1-3 Month T-Bill ETF), in the Financial Services sector, (Asset Management - Bonds industry), listed on AMEX.
The State Street SPDR Bloomberg 1-3 Month T-Bill ETF (BIL) is designed to closely mirror the price appreciation and income generation of the Bloomberg 1-3 Month U.S. Treasury Bill Index, prior to accounting for its operational costs. This fund primarily invests in government-issued U.S. Treasury Bills that have a remaining term of just one to three months. Due to this ultra-short maturity profile, the ETF exhibits lower sensitivity to shifts in interest rates compared to debt instruments with longer durations. Its holdings are adjusted and rebalanced on the last trading day of each month.
BIL (State Street SPDR Bloomberg 1-3 Month T-Bill ETF) trades in the Financial Services sector, specifically Asset Management - Bonds, with a market capitalization of approximately $47.00B, a beta of 0.00 versus the broader market, a 52-week range of 91.26-91.78, average daily share volume of 10.3M, a public-listing history dating back to 2007. These structural characteristics shape how BIL etf options price implied volatility around earnings windows, capital events, and macro-driven sector rotations.
A beta of 0.00 indicates BIL has historically moved less than the broader market, dampening realized volatility and producing tighter expected-move bands per unit of dollar exposure. BIL pays a dividend, which adjusts put-call parity and shifts the ex-dividend pricing across the listed chain.
What is a butterfly on BIL?
A long call butterfly buys one lower-strike call, sells two ATM calls, and buys one higher-strike call, paying a small net debit for a defined-risk position that maxes out if the underlying pins the middle strike at expiration.
BIL snapshot
As of August 14, 2026, spot at $91.53, ATM IV 1.90%, IV rank 0.21%, expected move 0.54%. The butterfly on BIL below is built from the August 14, 2026 end-of-day chain, with strikes snapped to listed contracts and premiums pulled from the bid/ask midpoint at a 35-day expiry.
Why this butterfly structure on BIL specifically: BIL IV at 1.90% is on the cheap side of its 1-year range, which favors premium-buying structures like a BIL butterfly, with a market-implied 1-standard-deviation move of approximately 0.54% (roughly $0.50 on the underlying). The 35-day window matched to the front-month expiry keeps theta exposure bounded while still capturing the post-snapshot move; longer-dated BIL expiries trade a higher absolute premium for lower per-day decay. Position sizing on BIL should anchor to the underlying notional of $91.53 per share and to the trader's directional view on BIL etf.
BIL butterfly setup
The BIL butterfly below is built from the August 14, 2026 end-of-day chain, with each option leg priced at the bid/ask midpoint of its listed strike. With BIL at $91.53 on that close, the first option leg uses a $86.95 strike; additional legs (when the strategy has them) anchor to spot-relative offsets. Premiums come from the bid/ask midpoint on the listed BIL chain at a 35-day expiry; the cross-strike IV skew is reflected directly in the per-leg values rather than approximated. Quantity sizing assumes one contract per option leg (or 100 BIL shares for the stock leg in covered calls and collars).
| Action | Type | Strike / Basis | Premium (est) |
|---|---|---|---|
| Buy 1 | Call | $86.95 | N/A |
| Sell 2 | Call | $91.53 | N/A |
| Buy 1 | Call | $96.11 | N/A |
BIL butterfly risk and reward
- Net Premium / Debit
- N/A
- Max Profit (per contract)
- Unbounded
- Max Loss (per contract)
- Unbounded
- Breakeven(s)
- None on modeled curve
- Risk / Reward Ratio
- N/A
Max profit equals the wing width minus net debit times 100 (reached when the underlying pins the middle strike); max loss equals the net debit times 100. Two breakevens at lower-wing plus debit and upper-wing minus debit.
BIL butterfly payoff curve
Modeled P&L at expiration across a range of underlying prices for the butterfly on BIL. Each row is one sampled price point from the computed payoff curve; the full curve uses 200 price points internally before being summarized into 10 rows here.
When traders use butterfly on BIL
Butterflies on BIL are pinning bets - traders use them when they expect BIL to settle near a specific level at expiration (often the prior close, a round number, or the max-pain strike) and want defined-risk exposure to that outcome.
BIL thesis for this butterfly
The market-implied 1-standard-deviation range for BIL extends from approximately $91.03 on the downside to $92.03 on the upside. A BIL long call butterfly is a pinning play: it pays maximum at the middle strike if BIL settles there at expiration, with the wing legs capping both the cost and the maximum loss to the net debit. Current BIL IV rank near 0.21% sits in the lower third of its 1-year distribution, where IV often re-expands toward the mean; this favors premium-buying structures and disadvantages premium-selling structures on BIL at 1.90%. As a Financial Services name, BIL options can move on sector-level news flow (peer earnings, regulatory updates, industry-specific macro data) in addition to BIL-specific events.
BIL butterfly positions are structurally neutral / pin (limited-risk, limited-reward); the modeled P&L assumes European-style exercise at expiration and ignores early assignment, transaction costs, dividends paid before expiry on the stock leg (when present), and the bid-ask spread on the listed chain. BIL positions also carry Financial Services sector concentration risk; news flow inside the sector (peer earnings, regulatory shifts, supply-chain headlines) can move BIL alongside the broader basket even when BIL-specific fundamentals are unchanged. Always rebuild the position from current BIL chain quotes before placing a trade.
Frequently asked questions
- What is a butterfly on BIL?
- A butterfly on BIL is the butterfly strategy applied to BIL (etf). The strategy is structurally neutral / pin (limited-risk, limited-reward): A long call butterfly buys one lower-strike call, sells two ATM calls, and buys one higher-strike call, paying a small net debit for a defined-risk position that maxes out if the underlying pins the middle strike at expiration. With BIL etf at $91.53 on the August 14, 2026 close, the strikes shown on this page are snapped to the nearest listed BIL chain strike and the premiums come straight from that session's bid/ask midpoint.
- How are BIL butterfly max profit and max loss calculated?
- Max profit equals the wing width minus net debit times 100 (reached when the underlying pins the middle strike); max loss equals the net debit times 100. Two breakevens at lower-wing plus debit and upper-wing minus debit. For the BIL butterfly priced from the August 14, 2026 end-of-day chain at a 30-day expiry (ATM IV 1.90%), the computed maximum profit is unbounded per contract and the computed maximum loss is unbounded per contract. Live intraday quotes will differ as the chain moves through the trading session.
- What is the breakeven for a BIL butterfly?
- The breakeven for the BIL butterfly priced on this page is no defined breakeven on the modeled curve at expiration, derived from the August 14, 2026 end-of-day chain's premiums. Breakeven is the underlying price at which the strategy's P&L crosses zero ignoring transaction costs and assignment risk. The BIL market-implied 1-standard-deviation expected move in the same options snapshot is approximately 0.54%; if the move sits well outside the breakeven distance, the structure's risk-reward becomes correspondingly tighter.
- When should you consider a butterfly on BIL?
- Butterflies on BIL are pinning bets - traders use them when they expect BIL to settle near a specific level at expiration (often the prior close, a round number, or the max-pain strike) and want defined-risk exposure to that outcome.
- How does current BIL implied volatility affect this butterfly?
- BIL ATM IV is at 1.90% with IV rank near 0.21%, which is on the low end of its 1-year range. Premium-buying structures (long call, long put, debit spreads) are relatively cheap in this regime; premium-selling structures collect less credit per unit risk.