Buying a spot bitcoin ETF share gives an investor a claim on bitcoin held by a custodian named in the fund’s structure, processed through a brokerage account. Holding bitcoin in self-custody means controlling the private key directly, with no custodian standing between the holder and the asset. Which one someone chooses changes who bears custody risk — it does not change the fee-drag question, because no source here provides expense-ratio or self-custody cost data to compare.
Who actually holds the bitcoin — and a contradiction in the record
Jean-Marie Mognetti, CEO of CoinShares, told a May 2026 Consensus Miami panel that ETF issuers are, in his words as quoted by CoinDesk, “all using one custodian, which is Coinbase,” and called that a concentration risk, comparing it unfavorably to the multi-prime-broker diversification a hedge fund would seek.
CoinDesk’s own reporting in the same article complicates that claim. It names Fidelity Digital Assets as custodian for Fidelity’s FBTC, Gemini and later Coinbase for VanEck’s HODL, Coinbase alongside Anchorage Digital Bank for BlackRock’s IBIT, and Coinbase Custody alongside BNY for Morgan Stanley’s proposed fund. That is five distinct custodial entities named across the funds CoinDesk cites — Fidelity Digital Assets, Gemini, Coinbase, Anchorage Digital Bank and BNY — not one. It is a gap between Mognetti’s quoted warning and CoinDesk’s own custodian list that the article does not resolve.
What the ETF wrapper actually holds
As of the same May 2026 CoinDesk report, roughly a dozen US spot bitcoin ETFs held about $107 billion in combined assets. Christopher Russell, head of strategic planning and analysis at Calamos Investments, broke that down on the panel: about $20 billion sat with institutional hedge funds, $12.5 billion had been allocated by registered investment advisors (RIAs), and 60% sat in direct retail accounts, according to CoinDesk’s reporting of his remarks.
Russell set that $12.5 billion RIA figure against the $146 trillion in advisor-managed assets under management, calling it, in his words as quoted by CoinDesk, “a really small number.” He described a barrier he called the “1% problem”: an advisor can take a small position in a volatile asset but is reluctant to spend meeting time explaining a sharp drawdown, per his comments to CoinDesk.
The futures-based alternative, and a demand-side data point
Not every bitcoin ETF holds bitcoin directly. ProShares’ BITO, a futures-based fund launched in October 2021, held about $2 billion in assets and traded at 35% of the daily volume of BlackRock’s spot IBIT, per Simeon Hyman, ProShares’ global investment strategist, cited by CoinDesk in May 2026. A futures-based structure changes the custody question again: exposure runs through futures contracts rather than custodied coins.
CoinDesk’s reporting also noted that Strategy, described as the largest corporate bitcoin holder with 818,334 BTC, reported a roughly $12.5 billion net loss for the first quarter of 2026 and signaled it could sell bitcoin to help meet dividend obligations — a reminder that corporate holding structures carry their own risks distinct from either ETF custody or personal self-custody.
The “preference, not conflict” view
Writing for Cointelegraph in January 2024, before US spot ETFs had launched, reporter Helen Partz gathered a range of views on whether ETFs and self-custody compete. Samson Mow, CEO of Jan3, said ETFs are built for funds and institutions that cannot hold the underlying asset, adding, in his words as quoted by Cointelegraph, that “ETFs don’t really compete with Bitcoin, they are a poor substitute for the underlying asset; however, they are useful as a bridge solution as legacy finance adapts to the new Bitcoin reality.” Leah Wald, then CEO of Valkyrie, called it “a matter of preference.” Bloomberg ETF analyst Eric Balchunas compared the choice to owning gold bars versus gold exposure, saying most people “aren’t that into it” when it comes to handling the physical asset themselves. Trezor analyst Josef Tětek took the opposing view, telling Cointelegraph that spot ETFs could pull people “further from self-custody” and introduce systemic risk by appearing safer than exchanges on the surface.
What this page does not tell you
This page cannot compare fee drag or total cost of ownership between spot bitcoin ETFs and self-custody. Neither source supplies expense ratios, tracking-error data, or the costs of self-custody such as hardware wallets or network fees — despite that comparison being the original premise for this page.
The custody-concentration claim from CoinShares’ Mognetti comes from a single conference panel remark, not an audited breakdown of which custodian holds what share of ETF-held bitcoin. This page cannot verify or quantify the concentration he describes, only note that CoinDesk’s own custodian list names five separate firms.
The Cointelegraph reporting is dated January 2024, before US spot bitcoin ETFs had launched. Its “no conflict” consensus reflects anticipation of a product that did not yet exist in the US market, not two-and-a-half years of live trading experience — and this page cannot say whether Mow, Wald, Balchunas or Tětek hold the same views today.
No prospectus, 19b-4 filing, or custodian agreement was used as a primary source here. Every custody and structure claim traces to secondary reporting by CoinDesk and Cointelegraph, not the underlying legal documents that would let a reader verify custodian assignments directly.
Sources
Every fact above is attributed to one of these reports. Where they disagree, the article says so.
