Direct crypto
How to short a Bitcoin ETF
Four routes to a bearish bitcoin position — inverse funds, leveraged inverse, put options and borrowing shares — with the daily-reset decay maths spelled out.
There are four ways to take a bearish position on bitcoin through a brokerage account, and they have wildly different risk profiles. One of them is designed to be held for a single day and is routinely held for months by people who did not read the fund page. Another has a defined maximum loss. One has theoretically unlimited loss.
This page sets out all four with the arithmetic, because the decay maths on inverse products is the single most misunderstood thing in this corner of the market.
Four ways to do it
| Method | How | What it costs | Sensible holding period | Maximum loss |
|---|---|---|---|---|
| Inverse ETF (BITI, -1x) | Buy the fund like any share | Expense ratio plus daily-reset decay | Intraday to a few days | Loss limited to your investment |
| Leveraged inverse (SBIT, -2x) | Buy the fund like any share | Higher fee, amplified decay | Intraday only, realistically | Loss limited to your investment |
| Put options on IBIT | Buy puts through an options-approved account | The premium you pay | To expiry, defined in advance | Loss limited to the premium |
| Short the shares | Borrow and sell in a margin account | Borrow fee plus margin interest | Open-ended | Theoretically unlimited loss |
Options and short selling both require account approval, and shorting requires a margin account. Availability differs by broker and account type — retirement accounts generally prohibit short selling.
Inverse funds and the daily reset
BITI, the ProShares Short Bitcoin ETF, was the first US fund to provide inverse bitcoin exposure. It targets -1x the daily performance of bitcoin, and the mechanics are worth stating precisely: it does not take a short position in bitcoin directly. To obtain inverse exposure it invests primarily in standardised, cash-settled CME bitcoin futures contracts, along with swaps.
The phrase that does all the work is daily performance. The fund reprices its exposure at the end of every trading day so that the next day starts fresh at -1x. That makes the stated multiple accurate for one day and unreliable for any longer period. ProShares' own materials state that returns can vary significantly from -1x if held longer than a day, and describe the fund as a short-term trading tool rather than a long-term investment.
SBIT applies the same structure at -2x, targeting twice the inverse of bitcoin's daily move. Every problem below is amplified.
The decay maths, worked through
This is where people lose money without understanding why. Take a -1x product and a market that goes nowhere over two days but moves sharply within them.
| Day | Bitcoin move | Inverse fund move | Fund value from $100 |
|---|---|---|---|
| Start | — | — | $100.00 |
| Day 1 | −20% | +20% | $120.00 |
| Day 2 | +25% (back to start) | −25% | $90.00 |
| Net | 0% — bitcoin is unchanged | — | $90.00 — you are down 10% |
Bitcoin ended exactly where it started. The inverse product lost 10%. This is volatility decay, and it is a structural feature of daily-reset products, not a tracking error.
Nothing went wrong in that example. The fund delivered -1x each day, exactly as designed. The loss comes from compounding daily returns in a volatile market, and it applies to leveraged long products too. On a -2x product the same two days produce a considerably larger loss.
Bitcoin is one of the most volatile liquid assets available, which makes it close to the worst possible underlying for a daily-reset product held over time.
Put options: defined risk, no decay of that kind
Buying a put gives you the right to sell at a set strike price until expiry. If bitcoin falls, the put gains value. If it does not, the most you lose is the premium you paid.
For a bearish view held over weeks rather than hours, this is usually the cleaner instrument. There is no daily reset and no volatility decay of the compounding kind — you face time decay instead, which is predictable and priced into the premium when you buy.
Practically this means IBIT. It has the only genuinely deep listed options market among US spot Bitcoin funds, which is one of the concrete things its 0.25% fee and scale buy you — see the IBIT profile. You will need options approval from your broker, and options carry a per-contract fee, typically $0.65 at Fidelity, Schwab, Merrill Edge and E*TRADE.
Shorting the shares directly
In a margin account you can borrow shares of a spot Bitcoin ETF, sell them, and buy them back later. There is no daily reset, no roll cost and no expiry — the position tracks the fund one for one.
The costs are the borrow fee, which varies with share availability, and margin interest. The risk is the one that matters: a short position's loss is theoretically unlimited, because there is no ceiling on how far the price can rise. On an asset that has repeatedly doubled in months, that is not an academic concern. Margin calls can also force you out at the worst possible moment.
Retirement accounts generally prohibit short selling entirely, so this route is taxable-account only.
Or step aside rather than betting against it
Not holding an asset is a complete bearish position with no decay, no borrow fee and no expiry. If you want to hold some crypto while managing exposure, a licensed exchange lets you size it precisely — CEX.IO is registered with FinCEN as a money services business, licensed for money transmission across US states, and authorised in Gibraltar as a DLT provider.
The weekend gap cuts both ways
Bitcoin trades continuously; the fund does not. That structural mismatch is a problem for long holders and a genuine hazard for short positions.
If bitcoin rallies 15% over a weekend, a short position in a spot Bitcoin ETF opens Monday facing the full move at once. There was no trading in the fund while it happened, so there was no opportunity to exit at any price in between. A stop-loss order does not help — it triggers into the gap and fills wherever the market opens, not where you set it. The mechanics are in limit orders and execution.
For a borrowed short with unlimited theoretical loss, that is the scenario to size against.
What we would use, for what
- A view lasting hours to a couple of days: an inverse fund is fit for purpose here, which is exactly what it was built for.
- A view lasting weeks: a put option, for the defined maximum loss and no daily-reset decay.
- A hedge on an existing long position: a protective put, which lets you keep the position and cap the downside.
- A view lasting months: honestly, reduce the long position instead. Every instrument on this page carries a cost of carry that a smaller allocation does not.
- Never: a -2x daily-reset product held for more than a session, in a volatile market. The maths is against you regardless of whether your view is right.
Our take from the desk
The pattern we see most often is someone with a correct directional view losing money anyway, because they expressed it through a daily-reset product held for six weeks. Being right about bitcoin falling and still down 10% is a genuinely demoralising outcome, and it is entirely predictable from the fund's own documentation. If you are going to hold a bearish view for more than a couple of days, learn to buy a put or simply own less.