Registered Funds and the 1940 Act

Almost every mutual fund, ETF, and closed-end fund available to ordinary U.S. investors operates under the same piece of federal law: the Investment Company Act of 1940, usually just called the '40 Act. A fund that registers under it is legally an investment company, subject to a detailed rulebook covering everything from how much it can borrow to how its assets must be held to what it has to disclose — the tradeoff for being allowed to sell shares broadly to the retail public.

What the '40 Act actually requires

A few provisions do most of the work. Registered funds face strict limits on leverage: a fund generally can't borrow more than a small fraction of its assets, and using derivatives to create leveraged-like exposure requires the fund to hold offsetting cash or securities to cover the obligation. Fund assets must be held by an independent custodian, not by the fund manager itself, so the manager can never simply run off with client money — a rule that exists precisely because pooled investment fraud was common before 1940. Funds must also value their portfolios and calculate NAV regularly (daily, for open-end funds), disclose holdings and fees in a standardized prospectus, and have a board of directors that includes independent members whose job is explicitly to look out for shareholders rather than the manager.

Why hedge funds opt out

Hedge funds, private equity funds, and most other private investment vehicles deliberately structure themselves to avoid '40 Act registration, typically by relying on exemptions that cap how many investors they can have or require those investors to be wealthy, sophisticated "accredited" or "qualified" investors. In exchange for giving up the ability to advertise broadly and sell to the general public, these funds get to skip the leverage limits, disclosure requirements, and governance rules that registered funds must follow — which is exactly why hedge funds can run far more leveraged, concentrated, or illiquid strategies than any mutual fund is legally allowed to.

A concrete example: a strategy that wants to run at 3x leverage using borrowed money simply cannot be offered as an ordinary '40 Act mutual fund — the leverage limits forbid it directly. The same strategy can be run inside a hedge fund, sold only to accredited investors under a private placement exemption, precisely because it never registers under the 1940 Act and its stricter rules don't apply.

What this means in practice

Whenever a fund is broadly advertised and sold to retail investors, the '40 Act framework is very likely the reason it looks the way it does — daily NAV, capped leverage, an independent custodian, standardized disclosure — while private funds pursuing similar strategies but exempt from registration can look completely different in structure and risk.