New York State’s Department of Financial Services has proposed a rule that would allow for “shared appreciation” of a property’s value if an underwater loan is refinanced. The Department states that this will provide a helpful option for underwater homeowners facing foreclosure. If a homeowner were to take a shared appreciation mortgage, he or she would get a principal reduction (and thus lower monthly payments) in exchange for giving up as much as fifty percent of the increase in the home’s value, payable when the property is sold or the mortgage is satisfied.

The precise formula for the holder of the mortgage is as follows:

The Holder’s share of the Appreciation in Market Value shall be limited to the lesser of:

1. The amount of the reduction in principal (deferred principal), plus interest on such amount calculated from the date of the Shared Appreciation       Agreement to the date of payment based on a rate that is applicable to the Modified Mortgage Loan; or

2. Fifty percent of the amount of Appreciation in Market Value. Section 82-2.6(b).

The principal balance of a shared appreciation mortgage “shall be no greater than: (i) an amount which when combined with other modification factors, such as lower interest rate or term extension, results in monthly payments that are 31% or less of the Mortgagor’s DTI; or (ii) 100% of the Appraised Value.” Section 82-2.11(i). The proposed regulation contains mandatory disclosures for the homeowner, including some examples of how a shared appreciation mortgage can work.

How does this all play out for the homeowner? We should note that similarly situated homeowners can be treated differently in a variety of ways. Here are a few examples. First, two similarly situated homeowners with different incomes can receive different principal balances because of the DTI limitation contained in section 82-2.11(i). Second, similarly situated homeowners can receive different principal balances because their houses appraise for different amounts. And third, different rates of appreciation of homes can make two similarly situated homeowners give up very different absolute dollars in appreciated value.

All of this is to say that homeowners will have to consider many variables in order to evaluate whether a share appreciation mortgage is a good option for them. They should also know that what is a good deal for one homeowner may not be a good deal for a similarly situated one. It is unlikely that the mandatory disclosures will be sufficient to explain this to them in all of its complexity. It is not even clear that loan counselors could do a great job with this either.

I am not arguing that the share appreciation mortgage is a bad innovation. But I do think that lenders will be able evaluate when offering one is a good deal for them while homeowners may have trouble evaluating when accepting one is a good deal on their end. I would guess that many may take one for non-economic reasons — I want to keep my home — and just take their chances as to how it all will play out financially.