How Spot Bitcoin ETFs Work: Creation, Custody, and Fees

TL;DR. A spot bitcoin ETF is a US-listed exchange-traded fund whose only asset is bitcoin held in cold storage by a qualified custodian. Big broker-dealers called authorized participants mint and redeem the fund’s shares in large blocks, and it is that plumbing — not the price of bitcoin itself — that keeps the ETF trading tight to the value of the bitcoin it owns. The SEC greenlit the first US spot bitcoin ETPs in January 2024 (Grayscale Investments — Wikipedia), and the category has become the fastest-growing corner of the ETF market: BlackRock’s IBIT alone holds roughly $47B as of mid-2026.

“Spot” vs futures — why the distinction matters

A futures bitcoin ETF (the first US variant, launched in October 2021) holds regulated CME bitcoin futures and rolls them month to month. Because bitcoin futures usually trade in contango — longer-dated contracts more expensive than near-dated ones — the fund pays a small roll cost each period, and its performance can drift below the price of bitcoin over long holding periods. That same drag is what bleeds commodity-futures ETFs versus their spot benchmark.

A spot bitcoin ETF instead holds actual bitcoin. When the fund takes in a dollar, that dollar (or an equivalent in bitcoin) ends up bought and moved to cold-storage wallets held by the custodian. There is no roll, no futures curve, no contango tax. The trade-off is that spot funds have to deal with 24/7 crypto markets, single-custodian concentration, and the operational risk of holding a bearer digital asset.

The January 2024 approval, in one paragraph

After more than a decade of denied applications and a 2023 court loss to Grayscale (Grayscale Investments — Wikipedia), the SEC approved a batch of spot bitcoin exchange-traded products in January 2024. Trading began the next session and eleven products listed on NYSE Arca, Nasdaq, and Cboe BZX. Grayscale’s existing GBTC closed-end trust converted into an ETF on the same day, and issuers including BlackRock, Fidelity, Bitwise, ARK/21Shares, VanEck, Invesco/Galaxy, Franklin Templeton, WisdomTree, Valkyrie, and Hashdex all went live in the same window. The launch went from concept to open trading almost overnight because sponsors had been queued up for months.

How creation and redemption actually work

Every ETF, spot bitcoin included, uses the same primary-market plumbing. Wikipedia’s ETF entry summarises it cleanly: shares are created and redeemed when large broker-dealers called authorized participants (APs) transact directly with the fund in large blocks called creation units, typically 50,000 shares (Exchange-traded fund — Wikipedia).

The loop looks like this:

  • When ETF demand pushes the market price above NAV, an AP delivers the underlying asset (or cash) to the fund and receives new ETF shares. It sells those shares into the market and pockets the premium.
  • When the ETF trades at a discount to NAV, an AP buys ETF shares in the open market, delivers them back to the fund, and receives the underlying asset (or cash), which it can sell in the spot market. It pockets the difference.

That arbitrage is what keeps the ETF glued to its net asset value. If NAV is $50 and the ETF is trading at $50.30, an AP with capital and access to the underlying will keep creating shares until the premium collapses. Retail investors never touch the primary market — they trade only in the secondary market on the exchange — but they benefit from the AP’s arbitrage.

The authorized-participant creation loop for a spot bitcoin ETF Diagram showing the authorized participant sending cash or bitcoin to the fund sponsor, the sponsor issuing new ETF shares back to the AP, the AP selling shares on the exchange to end investors, and cold-storage custody of the bitcoin. Authorized Participant (broker-dealer) Fund Sponsor (BlackRock, Fidelity, Bitwise, Grayscale…) Custodian (Coinbase Custody, Fidelity Digital, etc.) Exchange (NYSE Arca, Nasdaq, Cboe) Cash / BTC New ETF shares BTC to cold storage Secondary-market sale to end investors
Source: Adapted from Exchange-traded fund — Wikipedia. Retail investors trade only in the exchange leg; APs handle the primary-market mint/redeem.

Cash creation vs in-kind creation

Two flavours of creation coexist:

  • In-kind. The AP delivers the actual asset (in this case, bitcoin) to the fund and receives ETF shares. No coin has to be bought or sold by the fund itself. This is how most traditional equity ETFs work — it minimises fund-level trading costs and, in the US, is more tax-efficient because it avoids realising capital gains inside the fund.
  • Cash. The AP delivers cash to the fund, and the fund (or its trading agent) then goes to market and buys the bitcoin. Redemptions mirror this: the fund sells bitcoin and hands back cash. The fund books trading costs and any small tracking slippage.

Every US spot bitcoin ETP launched in January 2024 was required to use cash creation and redemption at launch. That was a deliberate design constraint driven by broker-dealer rules that did not, at the time, allow APs to hold bitcoin directly. In-kind was the industry’s preferred model and has since been introduced for spot bitcoin ETPs following further regulatory review. In practice the retail investor experience is nearly identical either way — but on a tax-efficiency basis, in-kind is the better long-run structure.

The largest US spot bitcoin ETFs

Ticker Fund name Sponsor Expense ratio Net assets (USD) Inception
IBIT iShares Bitcoin Trust ETF BlackRock 0.25% $46.52B Jan 2024
FBTC Fidelity Wise Origin Bitcoin Fund Fidelity 0.25% $10.81B Jan 10, 2024
GBTC Grayscale Bitcoin Trust ETF Grayscale 1.50% $8.39B Sep 2013 (converted 2024)
BITB Bitwise Bitcoin ETF Bitwise 0.20% $2.33B Jan 10, 2024
Sources: Yahoo Finance fund pages for IBIT, FBTC, GBTC, and BITB. AUM figures as of August 2026. Other US spot bitcoin ETFs include ARKB (ARK/21Shares), HODL (VanEck), BTCO (Invesco Galaxy), BRRR (Valkyrie), EZBC (Franklin), BTCW (WisdomTree), and DEFI (Hashdex).

Custody: the concentration you should notice

A spot bitcoin ETF is only as safe as the wallet holding its coins. Custodians in this market are “qualified custodians” under state trust law or federal banking law, most commonly the Coinbase Custody Trust Company, a New York limited-purpose trust chartered by the New York State Department of Financial Services. At the launch of the January 2024 batch, Coinbase was disclosed as the custodian for the majority of the approved products, with Fidelity using its in-house Fidelity Digital Assets Services (also an NYDFS trust). Gemini Trust is the primary custodian for VanEck’s HODL.

The concentration matters. If Coinbase Custody suffered a serious operational failure, half a dozen ETFs would be affected at once. Coinbase publishes segregated-wallet attestations and has never lost customer funds, but a would-be investor should know that this is the single largest operational risk in the category. Fund prospectuses spell it out in the risk-factor sections.

Fees and the fee war

The 2024 launch triggered the sharpest ETF fee war in memory. Bitwise opened bidding with a six-month, up-to-$1B fee waiver at 0%. BlackRock, Fidelity, ARK/21Shares, and others followed with waivers or below-cost headline fees ranging from 0.19% to 0.30%. Grayscale’s GBTC kept its legacy 1.50% expense ratio and spent 2024 haemorrhaging assets to the cheaper newcomers — billions of dollars per week for the first two months.

Grayscale eventually launched a “Mini” version of GBTC in July 2024 at a competitive fee, and moved a portion of GBTC’s bitcoin into the new share class to give holders a cheaper alternative without triggering a taxable event (Grayscale Investments — Wikipedia). Even so, GBTC remains an outlier on price. If you are picking between two funds that hold the same asset, the expense ratio is the biggest lever you control.

Expense ratios of leading US spot bitcoin ETFs Bar chart comparing the expense ratio (in percent) charged by IBIT, FBTC, BITB, and GBTC. Expense ratio (%) Fund 0.0 0.5 1.0 1.5 0.25% IBIT 0.25% FBTC 0.20% BITB 1.50% GBTC
Source: Yahoo Finance fund pages for IBIT, FBTC, BITB, GBTC. Expense ratios are net of any active fee waivers and can change; check the fund page for the current number.

Tracking, premium/discount, and taxes

A well-run spot bitcoin ETF should trade within a few basis points of NAV during US market hours. When the ETF is closed at 4pm ET but bitcoin keeps moving overnight in Asian and European trading, the next morning’s open will re-price the ETF to catch up. Retail investors sometimes see this as “premium” or “discount” on their broker screen; it is really a timing mismatch, not a broken fund.

The one instrument that used to trade at a genuine, persistent discount to NAV was pre-conversion GBTC. Because it was a closed-end trust rather than an ETF, the AP arbitrage described above was not available. GBTC frequently traded at 30–50% below its net asset value in 2022–2023, a discount that only closed when the vehicle converted into an ETF in January 2024 and the AP loop switched on.

On taxes: US spot bitcoin ETFs are structured as grantor trusts. Investors are treated as if they own a pro-rata slice of the underlying bitcoin, and sales generate capital gains taxed at the standard long- or short-term rates (SEC Investor.gov — Mutual Funds & ETFs). There is no annual 60/40 futures treatment as with BITO-style futures ETFs, and no K-1 partnership form.

Where investors get themselves into trouble

  • Trading in the pre-market or after-hours. With no AP arbitrage active, thin liquidity can produce fills far from NAV. Use limit orders during regular hours.
  • Assuming all products track identically. They do, gross of fees. Net of the 1.25 percentage-point gap between BITB and GBTC, a decade’s worth of compounding is meaningful. Pick the cheapest solvent option.
  • Ignoring the custody line in the prospectus. Six of the largest funds use the same custodian. That is a systemic exposure a wrapping ETF does not eliminate.
  • Treating a spot bitcoin ETF as a hedge for a leveraged bitcoin position. It is a linear, unleveraged bitcoin exposure. It does exactly what bitcoin does — including the 60–80% drawdowns.

What to learn next

Once the mechanics click, three adjacent topics reward the effort. First, leveraged and inverse ETFs — the daily-reset math is a very different beast from a spot fund. Second, contango and roll yield in commodity ETFs, which is exactly the drag a spot bitcoin ETF avoids. Third, the SEC’s later approval of spot ether ETPs, which used the same primary-market plumbing and the same custodian playbook.

Sources

Disclosure: This article is for informational purposes only and is not investment advice.

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