Why do REITs issue equity so frequently compared to regular corporations?

The 90% distribution requirement means REITs retain almost no earnings, so unlike a normal company they cannot self-fund growth from retained cash flow - every meaningful acquisition or development must be financed externally with debt or equity. Since leverage capacity is finite and rating-constrained, REITs are structurally serial equity issuers, using follow-ons, ATM programs, and OP units. The discipline this imposes is real: issuance only creates value when the REIT's cost of capital is below the yield on what it buys - roughly, when the stock trades at or above NAV. This dynamic is also why REIT coverage is such an active capital-markets seat in banking: the clients come back to market constantly.