Subchapter M

Subchapter M is the part of the Internal Revenue Code governing the taxation of regulated investment companies (RICs) — mutual funds, closed-end funds, and similar pooled vehicles — as well as real estate investment trusts. It implements what's often called the conduit or pipeline theory: the fund acts as a mere conduit passing income through to shareholders, so that income should be taxed once at the shareholder level, not twice.

Two separate sets of rules are at work, and they are easy to confuse because both involve 90%. Eligibility to be treated as a regulated investment company depends on a qualifying-income test — at least 90% of gross income must come from dividends, interest, and gains on securities and similar sources — together with asset diversification requirements. The distribution requirement is a different test: to deduct what it pays out, a RIC must distribute at least 90% of its investment company taxable income to shareholders. A fund that meets both pays no corporate income tax on the earnings it distributes — it deducts those distributions — and is taxed only on any income it retains. REITs operate under a parallel structure, distributing at least 90% of taxable income to preserve their conduit status.

The practical effect is significant. Without Subchapter M, a mutual fund's dividends and interest would be taxed at the fund level and again when paid out, dragging down returns. With it, shareholders receive distributions and pay tax themselves — which also explains why funds make large taxable distributions near year end even when investors reinvest them.

Subchapter M appears on the SIE, Series 7, and Series 65 exams, usually tied to investment company taxation or REITs. Remember which 90% is which — qualifying gross income for eligibility, investment company taxable income for the distribution requirement — plus the conduit/pipeline vocabulary and the fact that qualifying means the fund escapes tax only on distributed income, not retained income.