In exchange for being put "above water" on the mortgage, the borrower is required to share any subsequent appreciation of the home with the government. Although the basic structure of the H4H program is appealing, some lenders have expressed concerns about its complexity and cost, including the requirement in many cases to undertake substantial principal write-downs.
In a home-host setting for example, tightening the macroprudential stance in the host could be circumvented if the home stance is loose and allows for a re-direction of intermediation through e.g. branches.