We jointly test the effects of two types of investor uncertainty, one related to future firm performance and unrelated to accruals (cash flow uncertainty) and one directly related to accrual estimation errors (accounting quality uncertainty). Distinct from prior studies, our uncertainty estimates are based on a matched‐firm design that minimizes the mechanical relation between the two uncertainty variables. We find a strong negative relation between cash flow uncertainty and multiple estimates of the cost of equity capital. With respect to accounting quality uncertainty, we find a strong positive association with both expected stock returns and implied costs of equity, but only in settings that control for cash flow uncertainty. Collectively, our results suggest the need to consider different types of investor uncertainty when examining how investor uncertainty affects the cost of equity capital. This article is protected by copyright. All rights reserved