The SEC has proposed a custody rule that could let registered investment advisers hold Bitcoin and other cryptocurrencies directly for clients, and advisers under the regime manage more than $100 trillion in assets, according to 24/7 Wall St. Until now, most advisers stayed out of managed crypto because the old rules required a qualified custodian without defining who could hold a private key. The catch: the SEC must finalize the rule first, and a 60-day comment period starts only once it appears in the Federal Register.
The practical answer to "which coins first" is already visible in the ETF data. As of September 25, 2026, US spot Bitcoin ETFs held $108 billion against $17.8 billion for Ethereum funds, per the same report. Custodians, not the SEC, will decide which assets advisers can actually access, and custodians already support the two largest assets. We covered a connected angle in What Altcoins Are and How They Differ From Bitcoin.
What does the proposed rule actually change?
The proposal updates the Investment Advisers Act of 1940 and the Investment Company Act of 1940. State trust companies could serve as custodians if they adopt written safeguarding policies and file annual audited financial statements. Registered broker-dealers could qualify based on customer protection standards. Regulated funds could expand crypto offerings, and under certain conditions airdropped coins could stay within the rules.
The timing matters. The SEC withdrew its 2023 custodial-safeguards proposal on June 12, 2025, leaving a gap until now, per 24/7 Wall St. SEC Chair Paul Atkins said crypto has evolved "from a niche curiosity into a multi-trillion-dollar asset class" since the 2008 Bitcoin white paper, and that "our rules and regulations have not kept pace." The proposal follows a series of SEC crypto rules in September, after the Senate failed to advance the CLARITY Act.
Why is self-custody option likely a dead end for most advisers?
The proposal does allow advisers to hold private keys themselves. The conditions are heavy, and that is the point. An adviser must first demonstrate it could not find an approved custodian for the asset. At least two people must authorize any use of the keys. Each client's coins must sit in separate addresses. An independent auditor must evaluate custody controls within six months, and fund boards review the adviser's determination quarterly.
Read the mechanism, not the headline. Those requirements make self-custody expensive enough that most advisers will not attempt it. That pushes them toward coins custodians already support. The rule's practical effect is not "advisers can hold anything." It is "advisers can hold what custodians list," which is a narrower set decided by private companies, not the regulator.
Which coins see adviser money first?
Bitcoin is positioned to reach adviser accounts first, with Ethereum likely next, because custodians already support both assets. The ETF numbers reinforce that ordering. Bitcoin funds control roughly six times Ethereum's total and more than fifty times Solana's $2 billion, while XRP funds held $1.8 billion. Bitcoin funds already own 6.29% of all Bitcoin, per the report.
For altcoins beyond those four, the path is conditional. If the final rule includes a broader custodian list and relaxes self-custody requirements, smaller assets like Solana and XRP could enter advised accounts faster. If not, the rule mostly extends the advantage Bitcoin and Ethereum already hold. How a token's float and liquidity absorb new demand matters too; that dynamic is covered in How Token Liquidity and Float Shape Altcoin Price Moves.
What should market participants watch from here?
Three things decide whether this becomes a real flow or stays on paper. First, the comment period and final text: the proposal is not law, and the self-custody conditions could tighten or loosen. Second, custodian listings: each new asset a qualified custodian supports is the actual gate for adviser money. Third, whether the final rule's custodian definition expands enough to include the state trust companies and broker-dealers the proposal names.
For readers tracking how regulated money enters this market, the ETF allocations are the cleanest public signal of where adviser accounts will concentrate, and the broader context sits in our crypto news coverage. The evidence so far supports one reading: the proposal removes the primary legal barrier that kept advisers away, but the ordering of which assets benefit is being set by custodians and existing ETF flows, not by the SEC.
This article is for general information only and is not financial or investment advice.
