Most estimates of the welfare costs of in ation are devised considering only noninterest-bearing assets, ignoring that since the 80 s technological innovations and new regu-lations have increased the liquidity of interest-bearing deposits. We investigate theresulting bias. Su¢ cient and necessary conditions on its sign are presented, alongwith closed-form expressions for its magnitude. Two examples dealing with bidimen-sional bilogarithmic money demands show that disregarding interest-bearing moniesmay lead to a non-negligible overestimation of the welfare costs of in ation. An intu-itive explanation is that such assets may partially make up for the decreased demandof noninterest-bearing assets due to higher in ation.