IBIT vs FBTC: What Is the Difference Between the Two Bitcoin ETFs?

Are IBIT and FBTC the same kind of fund?

Mechanically, yes. IBIT (iShares Bitcoin Trust, sponsored by BlackRock) and FBTC (Fidelity Wise Origin Bitcoin Fund) are both US spot Bitcoin ETFs: exchange-listed funds that hold Bitcoin itself, not futures contracts or mining stocks. Both were approved together and began trading on the same day — January 11, 2024 — as part of the first cohort of US spot Bitcoin funds.

Because the wrapper is identical, the comparison is less “two different products” and more “the same product from two manufacturers.” A dollar into either fund ends up as Bitcoin held by a custodian, and a dollar out forces Bitcoin to be sold:

That shared mechanism is also what separates both funds from perpetual futures, the other common route to Bitcoin exposure: an ETF share is backed by coins in custody and charges a management fee, while a perp is a leveraged contract that charges funding and never holds the asset. Where the two funds genuinely differ is scale, liquidity and custody — the rest of this article measures those gaps with live data.

IBIT vs FBTC head-to-head: the live numbers

The table below is generated from the latest daily snapshot on Coinfuty’s Bitcoin ETF flow tracker — the same numbers the fund pages report, refreshed each trading day. A dash means the fund has not reported that figure yet.

Live reading: IBIT currently reports about $46.96B in assets to FBTC's $11.00B, roughly 4.3× the size — 746,478 BTC in the vault against 172,069 BTC.

Notice what the table does not show: a performance gap. Because both funds hold the same asset and charge the same fee, their returns are effectively identical — every visible difference lives in size, turnover and structure.

Size and liquidity: how far ahead is IBIT?

Scale is where the two funds parted ways. Launched on the same day, IBIT pulled steadily further ahead through 2024 and 2025 and became the reference fund of the category, while FBTC settled into a solid second tier alongside the converted Grayscale trust. The donut shows how assets are distributed across the whole US spot-ETF field right now:

Size compounds into liquidity. The bigger fund attracts more two-way order flow, which narrows spreads, which attracts the institutions that care most about execution cost — a loop that keeps reinforcing the leader. It also gave IBIT the more active listed-options market, one more layer of trading activity anchored to its shares. In the latest session, about $5.40B of IBIT changed hands versus $645.13M of FBTC — a gap of 8.4× in dollar turnover, which is what keeps IBIT's quoted spreads the tightest of the group.

Fees and custody: where the two funds actually differ

On headline cost the rivalry is a stalemate: both funds charge a 0.25% annual sponsor fee, both waived part of it at launch to compete for early assets, and neither has blinked since the waivers lapsed. For context, the converted Grayscale trust (GBTC) kept its fee several times higher — it still lists 1.5% today, a gap that goes a long way toward explaining the persistent outflows from GBTC in the flow table below.

The structural difference sits in custody. IBIT follows the standard model: its Bitcoin is held by Coinbase Custody Trust, a third-party custodian, with the usual cold-storage arrangements. Fidelity chose to keep the whole stack in the family — FBTC’s Bitcoin is custodied by Fidelity Digital Asset Services, an affiliate of the sponsor itself. FBTC is the notable self-custody exception among the large US spot funds.

Whether third-party or affiliated custody is preferable is a question about counterparty structure, not about returns — the coins exist either way, and both arrangements sit under the same regulatory reporting regime. What matters for a comparison is simply that this is the one place where the two funds made genuinely different design choices.

What the flow data shows

Daily net flow — creations minus redemptions, in dollars — is the cleanest live measure of which fund is winning new money. It is worth reading correctly: flows track demand for the wrapper, not the performance of the Bitcoin inside it, and in risk-off stretches every fund in the cohort can print red at once. Here is the past 60 trading days summed per fund:

The head-to-head version of the same data subtracts FBTC’s daily flow from IBIT’s and accumulates the difference: when the line rises IBIT is out-gathering FBTC, when it falls the gap is running the other way. Over the past 60 trading days, IBIT has actually given back about $2.69B more in net dollars than FBTC — dollar flows scale with fund size in both directions, so the bigger fund also posts the bigger outflow totals in a drawdown.

A dollar gap, in either direction, mostly restates the size gap — a fund four times larger produces flow numbers on a four-times scale, inflows and outflows alike. The more interesting signal is usually the cohort-wide total, which says whether ETF investors as a group are adding or shedding Bitcoin exposure; that series, fund-by-fund matrix and per-fund history all update daily on the Bitcoin ETF flow tracker. For how share-price premiums relate to arbitrage more generally, the basis trading explainer covers the same convergence logic in futures form.

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