To temporarily exempt the sale of a principle residence that becomes the buyer’s principle residence from the higher property taxes caused by the Proposal A taxable value “bump-up.” The “bump up” is where the state equalized value (market value) of newly-sold property becomes the basis for its property tax assessment, rather than the capped “taxable value” of the previous owner, which has traditionally been lower. The exemption would be in effect from 2013 through 2017.   Official Text and Analysis.