I build a model of neoclassical production to examine the capital market and welfare effects of a uniform accounting standard (like IFRS). Firms vary in their cost of compliance to the standard, and investors vary in their cost of learning diverse standards for capital allocation. A uniform accounting standard increases the quantity of capital in the economy and lowers the cost of capital. However, uniform standards force diverse firms onto the same standard, which reduces welfare. A regulator selects the optimal number and type of standards to balance these competing effects. Uniform accounting standards are better than diverse accounting standards when firm productivity and variation between investors is large, but worse when the cost of investment and variation between firms is large. I draw implications for IFRS/GAAP convergence and the incentives versus standards debate.