Using micro data on managerial expenditures, we uncover heuristics in capital budgets, such as nominal rigidity, anchoring, and sharp reset deadlines. Such heuristics engender managerial opportunism. Managers with a budget surplus increase investment before budget deadlines, and such projects underperform. Managers who reach a budget constraint early in the fiscal cycle halt spending until their budget is reset, irrespective of investment options. These effects are stronger at firms with more hierarchical layers and a greater subordinates-to-executives ratio. Such firms become targets of private equity funds. After the buyout by strong principals, firms remove budgetary heuristics and switch to continuous capital allocations. Overall, simplifying budgeting rules engender strategic managerial behavior.