Cost of Capital - Valuation101

Module: `lib/cost_of_capital.py`

Implements the three WACC computation methods from Damodaran’s Cost of Capital worksheet.

Bottom-up WACC from first principles: unlevered beta → re-lever → CAPM → synthetic rating → cost of debt → weighted average.

Looks up industry average cost of capital from Damodaran’s reference dataset.

Returns the company’s WACC percentile within its industry — useful for sanity-checking the detailed estimate.

Maps interest coverage ratio to a bond rating and default spread using Damodaran’s synthetic rating table.

Re-levers an unlevered beta for a specific debt/equity ratio and tax rate.