Robert Buckley's comment [1] could usefully suggest that the benefits that mortgagors derive from tandem plans can be divided into two parts: (1) the primary cash-equivalent benefits to those obtaining below-market interest rate mortgages, and (2) any possible secondary benefits (damages) stemming frorn the decline (rise) in market rates as a result of GNMA's intermediation. I provided numerical estimates only for (1), but mentioned the possibility of secondary eSects, though I regarded the direction of tandem's eSect on market rates as quite uncertain [2, pp. 386-88]. Ronald Utt [6] has recently estimated that GNMA commitments may reduce the supply of mortgage credit from private sources and keep mortgage interest rates higher than they would be otherwise. Buckley seems to prefer the opposite assumption, in part because this is what other studies that antedate most or all of the extended tandem programs and the unpredictedly severe 197>75 housing slump appear to suggest. If the actual impact of tandem programs on market rates could be determined reliably, it would be easy to calculate the secondary income distribution eSects and to add them to the primary eSects. Unlike any estimate of the secondary eSects, my estimate of the primary eSects seems quite robust. For instance, using the familiar triangle rule for measuring consumer surplus, the cash equivalent primary benefits to mortgagors would be at most 7 percent less than I had estimated if twice as many tandemsupported homebuyers (100,000) were marginal than the 13 to 14 percent I had deduced for my special case. Furthermore, it seems to me that these primary eSects should be the main focus of any study attempting to appraise the income transfers generated by tandem programs. The equity aspects of the widely diFused secondary eSects are of no more immediate concern than those of shifts in the monetary-fiscal policy mix that occur all the time. By contrast, in estimating the eSect on housing starts of net purchases by federally sponsored credit agencies of tandem-supported mortgages or any others, any eSect on market rates and on the degree of rationing in the mortgage market would be critical. This, however, was not the subject of my paper.