Zillow research has found that 42.6 percent of Generation X homeowners (those aged from 35-49) have negative equity. Because of the difficulty that underwater Gen-X homeowners are having in selling their homes, the wide disparities among generations will continue to ripple throughout the housing market. Baby boomers, only 31.1 percent of which are underwater, may not be able to find move-up buyers for their homes, and millennials can’t move into the more affordable starter homes currently occupied by Gen X.