When an investor requires a lender to repurchase a loan because the loan doesn't meet investor guidelines, is the lender that repurchases the loan required to provide the mortgage transfer disclosure under the Helping Families Save Their Homes Act (Reg Z), assuming more than one acquisition in a 12-month period and transfer of ownership?

From my reading of the reg I would say yes, you must provide the notice; see 226.39(c). the commentary explains the limited exceptions and the repurchase exception is explained as applying to a temporary finance situation and not a loan that failed to meet investor guidelines.