Higher home prices are making house flipping harder and riskier but more lucrative. Flipping houses, which is generally defined as buying and selling a home in the same calendar year, is actually down slightly this year, but year-over-year, it’s been fifty percent more profitable. Home flips made up just 4.5% of sales in the second quarter this year, according to RealtyTrac, down from 4.9 percent a year ago. Flipping returns (the gross return on investment), however, increased to nearly 36 percent, up from 24 percent one year ago.