BlackRock files PBIT, a bitcoin ETF that caps the upside to limit losses near 10%

BlackRock has filed with the SEC for a bitcoin ETF with downside protection: the iShares Bitcoin Managed Protection ETF, ticker PBIT. The prospectus, filed on 19 October 2026 as an amendment to the iShares Trust registration, describes a fund that holds no bitcoin. It would buy and sell options on BlackRock’s own spot fund, the iShares Bitcoin Trust (IBIT), aiming to limit the loss of each options tranche to about 10% while capping how much of a rally investors keep. The management fee, the cap and the launch date are all left blank.

The filing asks for the amendment to take effect 75 days after filing, which points to 2 January 2027 at the earliest. That is the end of the SEC’s review window, not an approval and not a listing date.

James Seyffart, ETF analyst at Bloomberg Intelligence, counted it as BlackRock’s third bitcoin ETF filing, The Block reported. It comes as US spot bitcoin ETFs have just had two weeks of net outflows and bitcoin traded near $81,930 at 05:11 UTC on 20 October, by Coindaro’s market data.

What the PBIT filing says, and what it leaves blank

The document is a Form 485APOS, the route an existing fund family uses to register a new series under the Investment Company Act of 1940. The spot bitcoin funds of January 2024 were stand-alone trusts holding coins, and each needed the SEC to approve an exchange rule change. PBIT would instead be one more series of an existing 1940-Act fund family, an ordinary ETF that holds derivatives linked to bitcoin.

Its stated objective is to give “upside exposure to the iShares Bitcoin Trust ETF (IBIT) and/or similar bitcoin exposure up to an approximate limit” while seeking “a level of downside protection”. The prospectus also says plainly that the fund “does not invest directly in bitcoin or bitcoin exchange-traded products”. It would hold options, plus short-term bonds and cash, and no IBIT shares.

Here is what the filing fixes and what it does not:

• The name and ticker: iShares Bitcoin Managed Protection ETF, PBIT. Some outlets wrote “Managed Protect”; the filing says “Managed Protection”.
• The adviser is BlackRock Fund Advisors (BFA), and the named portfolio managers are Erin Armstrong, Kyle McClements and Richard Mejzak.
• The management fee and the total expense ratio are blank lines in the fee table, and the cost example is empty. Other expenses are shown at 0.00%.
• No cap value is given, because the cap of each tranche will depend on option prices on the day it is set.
• The listing exchange and the launch date are not stated; the prospectus date is blank apart from the year, 2027.
• At least 80% of net assets must go to instruments that give bitcoin exposure or carry out the strategy. The fund is non-diversified and intends to qualify as a regulated investment company for US tax purposes.

How BlackRock’s bitcoin ETF downside protection works: call spreads on IBIT

PBIT’s engine is a call spread. For each tranche, the fund buys call options whose strike sits below the bitcoin reference price on the start date, so they are already in the money. At the same time it sells call options with a higher strike. The bought calls give the bitcoin exposure. The sold calls bring in a premium that pays for part of the purchase, and in exchange they hand away any gain above their strike.

The rest of the money sits in cash, money market funds, short-term government debt and short-term investment-grade bonds. According to the prospectus, interest from these holdings “is intended to help offset the cost” of the options. The options are expected to be FLEX options, which are customised listed contracts, exercisable only at expiry and cleared by the Options Clearing Corporation; standard listed options may also be used.

A worked example with round numbers

The figures below are illustrative only; the filing gives no cap. Say the reference price is $100 on the day a tranche starts. The fund buys calls struck at $90 and sells calls struck at, for example, $115. Per $100 of exposure, roughly $10 goes into the call spread and roughly $90 stays in short-term bonds and cash.

• If the reference ends the tranche at $70, the calls expire worthless. The tranche is left with its bonds and cash, about $90: a loss near 10%, plus fees, plus or minus what the options cost beyond their intrinsic value and what the bonds earned.
• If it ends at $105, the spread is worth $15 and the tranche gains roughly as much as bitcoin did, before costs.
• If it ends at $140, the spread pays $25 at most, because every dollar above $115 is owed to the buyer of the sold calls. The tranche keeps about 15% while bitcoin made 40%.

The third case is what the protection costs. In a strong rally, the gap between bitcoin and the tranche widens with every dollar above the cap.

Three tranches, so no single 10% number for shareholders

The fund plans to run three overlapping tranches, each typically lasting about a calendar quarter, with start dates staggered by a month: one expires and a new one begins each month. BlackRock keeps “broad discretion” to run more or fewer tranches or to use other expiries.

The 10% figure belongs to each tranche, measured on the day its calls are bought. The strike of the bought calls, which the filing calls the Tranche Protection Start Value, is typically set at about 90% of the reference value on that day. That gives the tranche an initial maximum loss of approximately 10% before fees and expenses, and the prospectus names this the “Floor”. The fund may raise or lower the start value of any tranche at any time.

Two things follow for a buyer. If bitcoin has risen since a tranche started, the distance from today’s price down to that tranche’s floor is wider than 10%. And because three tranches with different start prices and caps sit in the fund at once, the prospectus says it does not provide a fixed start value, floor or cap, and investors “should not expect to experience the same investment outcome” as someone holding one tranche from start to finish. Bitcoin.com News made the same point: the 10% is a per-tranche target, not a guaranteed limit for shareholders.

The risk section is blunt. Investors “may lose some or all of their money”, and extreme volatility may significantly reduce both the upside the fund captures and the protection it gives. BlackRock says it will publish each tranche’s start value, cap, weight and holdings on iShares.com.

Why “bitcoin buffer ETF” is the wrong label for PBIT

Funds that trade bitcoin upside for protection are often lumped together as buffer ETFs, and PBIT will be searched that way. The difference matters, because the two designs protect opposite ends of a fall.

A classic buffer fund absorbs the first slice of a loss, say the first 10%, and the investor bears everything beyond it. A floor fund works the other way: the investor bears the first slice and is protected below it. PBIT, with calls bought about 10% under the start price, is built as a floor. In a 5% dip a PBIT tranche would lose about as much as bitcoin, before costs. In a 50% crash it would lose about 10%, before costs and timing effects.

Which one suits a holder depends on what they fear. A floor does little against small dips. It is insurance against a deep drawdown, paid for with the cap.

IBIT is the engine, and BlackRock says so

IBIT is the reference asset, and that makes the new fund another customer of the old one. The prospectus discloses that the fund’s use of options on IBIT “may result in additional assets in IBIT and indirectly increase fees to BFA and its affiliates”. IBIT charges its own fee on its assets, so BlackRock could earn twice on the same bitcoin exposure.

IBIT had $65.34 billion of net assets on 16 October, according to BlackRock figures cited by Bitcoin.com News; The Block puts it above $65 billion and calls it the largest bitcoin ETF by its tracker. It is a Delaware trust, listed on Nasdaq since January 2024, that tracks the CME CF Bitcoin Reference Rate New York variant. For a refresher on how these funds create and redeem shares, see our glossary entry on crypto ETFs.

PBIT is also the mirror image of BlackRock’s last bitcoin launch. The iShares Bitcoin Premium Income ETF (BITA) launched on 16 June 2026, according to Bitcoin.com News, and trades on Nasdaq, according to The Block. BITA sells call options on IBIT on about 25% to 35% of its portfolio, according to iShares, pays the premiums out monthly and gives up part of the upside to do it. PBIT also sells upside, but spends the proceeds on protection rather than paying them out.

The Block quoted Seyffart’s remark that BlackRock still has “only Bitcoin and Ethereum products”, while other companies have launched ETFs tied to XRP, Solana and Dogecoin. PBIT does not change that count.

Bitcoin protection ETFs already trade, and they are small

PBIT would not be the first US fund to sell bitcoin with a limit on losses. At least three designs already trade, and their issuer pages showed the following on 19 October:

The Calamos fund, launched on 22 January 2025, is the strictest: full protection over a year, with a cap that started at 8.36% gross on 2 February 2026. Calamos also lists series with 90% and 80% protection on its site. The First Trust FT Vest fund, which began on 30 September 2025, accepts a 15% loss in return for a far higher cap over a period running to 8 October 2027. Its reference asset is already IBIT, so BlackRock would not be the first to build a floor on its own spot fund; at $1.69 million, BFOC is also the smallest of the three.

The third tells the story of demand. Innovator’s page for QBF, which launched on 6 February 2025, now carries a liquidation notice: trading will halt at the close on 31 December 2026, and the fund will be liquidated on or about 8 January 2027. That is days after PBIT’s 75-day window would end.

Added up, the three funds in the table hold around $30 million, against IBIT’s $65 billion, or less than 0.05% of it. Whether a BlackRock label brings more buyers to the format is the open question; the filing gives no seed size and no sign of expected demand.

A protection fund filed during two weeks of ETF outflows

The timing fits the market mood. US spot bitcoin ETFs lost $681 million in the week of 5 to 9 October, the most since June, as we covered in our report on that weekly outflow. The following week, 12 to 16 October, they lost about another $229 million by Coindaro’s sum of SoSoValue daily data, a second losing week in a row.

On Monday 19 October, bitcoin rose to $83,000 in the morning and then gave the move back while US chip stocks rallied, as described in our analysis of the US session. By 05:11 UTC on Tuesday it traded near $81,930, down 0.76% over 24 hours.

Nothing in the filing ties it to these flows. But a buyer weighing a bitcoin fund after a run of outflows is the kind of buyer it targets: someone who wants exposure to bitcoin but fears a deep drawdown more than missing part of a rally.

Before PBIT can list: the 75-day clock and the missing numbers

Under the box BlackRock ticked, the amendment can become effective 75 days after filing, which is 2 January 2027 at the earliest. The SEC can comment in the meantime. The blanks for the fee, the share details and the prospectus date mean BlackRock would have to file again to fill them before any launch. Nothing in the filing commits to a date.

Several items remain unknown as of 20 October:

• The management fee, which the prospectus warns will reduce upside participation and increase potential losses. The three existing funds in the table charge 0.69% to 0.90%, and any PBIT fee comes on top of the indirect cost of the options.
• The level of the first caps. They depend on the price of bitcoin options on the day each tranche starts, and BlackRock will post them on iShares.com.
• The listing exchange, seed capital and market makers.

The dates to watch are 31 December, when QBF trading halts, and 2 January 2027, when PBIT’s review window can close.