How should a qualified lender disclose the cost of borrower stock or participation certificates?

The cost of borrower stock or participation certificates must be included in the effective interest rate calculation at the time the stock or participation certificate is purchased in connection with a loan transaction. For subsequent loans to existing borrowers, only the cost of new stock or participation certificates, if any, purchased in connection with a new loan or advance of new funds must be included in the effective interest rate calculation for the transaction.