Which laws or regulations require mortgage lenders to disclose financing costs and annual percentage rate to a borrower before funding a loan?

The Truth in Lending Act (TILA)

Explanation:

TILA was passed in 1968 in an attempt to protect loan consumers from unfair practices carried out by lenders. TILA requires lenders to disclose the credit terms in a simple and understandable manner so that potential consumers can compare credit terms offered by different lenders. The information disclosed must include the loan's APR, principal, finance charges, payment schedule and monthly payments.

TILA applies to most types of consumer credit, including car loans, home mortgages, credit card, home equity loans, etc.