How spot Bitcoin ETFs work: custody, creations and why the price tracks

A spot Bitcoin exchange-traded fund is the product that turned bitcoin from something an institution had to figure out how to hold into something it could buy with the same ticket it uses for an S&P 500 fund. The structure is old and well understood. What was new in 2024 was that US regulators finally allowed it to be pointed at bitcoin held directly, rather than at futures contracts, and the money that followed reshaped the market.

What the fund actually holds

A spot ETF is a trust that owns bitcoin outright. The coins sit with a regulated custodian, overwhelmingly Coinbase Custody for the US products, with a smaller number using Fidelity Digital Assets, Gemini or BitGo. The trust issues shares, each representing a fractional claim on the pool, and those shares trade on Nasdaq, NYSE Arca or Cboe like any stock. The sponsor charges a management fee, typically between 0.12 and 0.25 percent a year for the large issuers, which is deducted from the trust’s holdings so the bitcoin per share declines very slowly over time.

This is distinct from the futures-based ETFs approved in 2021, which held CME bitcoin futures rather than coins and suffered from the cost of rolling contracts each month. It is also distinct from the Grayscale Bitcoin Trust in its original form, which for years traded at large premiums and discounts to its holdings because it had no redemption mechanism. Grayscale’s court victory against the SEC in August 2023 was the legal turning point that made the January 2024 approvals all but inevitable.

How creations and redemptions keep the price honest

The feature that makes an ETF an ETF is the creation and redemption process. A small set of large broker-dealers called authorized participants can deliver assets to the trust and receive new shares in blocks of, say, 10,000 or 40,000, or hand shares back and take assets out. If the ETF trades above the value of its bitcoin, an AP creates shares and sells them, pushing the price down. If it trades below, an AP buys shares and redeems them. That arbitrage is why spot ETFs track their net asset value within a few basis points, where the old Grayscale trust could drift 40 percent away.

At launch the SEC insisted on cash creations: the AP delivers dollars, the trust buys bitcoin, and the reverse on redemption. That kept broker-dealers from touching bitcoin directly but added trading costs and made the funds less tax efficient. In July 2025 the Commission approved in-kind creations and redemptions, the standard model for commodity and equity ETFs, so APs can now deliver and receive bitcoin itself. Most of the major issuers filed to adopt the change within weeks.

The scale of what happened

Eleven spot Bitcoin ETFs began trading on January 11, 2024. BlackRock’s iShares Bitcoin Trust (IBIT) became the fastest ETF ever to reach $10 billion, then $50 billion, and by 2025 had passed the assets of the firm’s own gold fund. Collectively the US spot products absorbed tens of billions of dollars of net inflows in their first year and came to hold well over a million bitcoin, more than 5 percent of the total supply, which made ETF flow data a daily market signal in its own right. Spot Ether ETFs, approved in May 2024 and launched that July, gathered assets more slowly until the ability to stake the underlying ether inside the fund was clarified.

The demand came from a mix of registered investment advisers allocating on behalf of clients, hedge funds running basis trades between the ETF and CME futures, and a growing list of institutions whose mandates permit exchange-listed securities but not direct crypto holdings. That last group is the reason the ETF mattered structurally: it moved bitcoin inside the perimeter of existing compliance, custody and reporting systems rather than asking those systems to change.

What an allocator should look at

The products are close substitutes, so the decision usually comes down to a short list of factors. Fee is the obvious one, but at the level of a few basis points it matters less than liquidity: the largest funds have the tightest bid-ask spreads and the deepest options markets, which is where much of the institutional activity now happens. Custodian concentration is a real consideration, since a single custodian holds the majority of ETF bitcoin. Tax treatment depends on the wrapper and the holder’s jurisdiction, and the in-kind change improved it for the funds themselves. Finally, an ETF gives price exposure and nothing else: no ability to move coins on-chain, no staking or lending yield in the Bitcoin products, and no self-custody. For many institutions that is precisely the point.

Beyond Bitcoin and Ether

The SEC’s adoption of generic listing standards for commodity-based exchange-traded products in September 2025 removed the need for a separate rule change for each new crypto asset, opening the door to spot ETFs on Solana, XRP and others that launched through late 2025 and 2026. Multi-asset index products and funds that stake their holdings followed. The same creation and redemption mechanics apply; what differs is the liquidity and custody depth of the underlying asset, which is thinner outside the top two and worth examining before assuming a new product will track as tightly as IBIT does.