Early-stage uncertainty makes the initial cost of capital greater than the expansion-stage one. Tax effects on enterprise formation, entrepreneurial effort and quality, and on capital costs are derived. For an incorporated enterprise (i) the entrepreneur?s ability threshold rises with the tax rate of the corporate form, (ii) the initial cost of capital due to a dividend tax is above the old view double-tax one, (iii) the start-up investment is not affected by undervaluation, but the discouragement engendered by dividend taxation is compensated by realization-based capital gains tax, (iv) with undervaluation, the expansion-stage cost of capital corresponds to the Johansson-Samuelson tax which is lower than the new view suggests, (v) without undervaluation, the dividend tax boosts expansion investment.