In just the past 40 years there were two other housing bubbles, with peaks in 1979 and 1989, but the largest one in U.S. history started in 1997, probably sparked by rising household income that began in 1992 combined with the elimination in 1997 of taxes on residential capital gains up to $500,000. Rising values in an asset market draw investor attention; the early stages of the housing bubble had this usual, self-reinforcing feature.