<p>In this paper, we use data from the British Household Panel Survey (BHPS) for the years 1992 to 1998 to study the determinants of saving in the form of voluntary contributions to personal pension plans (PPPs). We first estimate a probit model with selection for the probability of making these voluntary contributions. We then estimate a random-effects tobit regression for the amounts contributed and compare the results with those of a similar regression for conventional saving. Our findings suggest that voluntary contributions to PPPs are made essentially for retirement purposes, whereas conventional saving is undertaken for precautionary motives. The former type of saving is thus unlikely to offset the latter completely.</p>