Seattle, Portland and Dallas are leading the country in home price gains since last spring, with no slowdown in sight. Dallas-area home prices rose 8.4 percent in the latest Standard & Poor's/Case-Shiller Home Price Index. Nationwide, prices in April were 5.5 percent higher from a year earlier. North Texas home prices are at an all-time high and have risen by more than 50 percent in the last five years. "As home prices continue rising faster than inflation, two questions are being asked: why? And, could this be a bubble?" S&P's David M. Blitzer said in the report. "Since demand is exceeding supply and financing is available, there is nothing right now to keep prices from going up. Through the first five months of 2017, prices of North Texas homes sold by real estate agents have jumped 12 percent higher than the same period last year. The median sales price for preowned single-family homes in the area is $255,000 — slightly ahead of the national median price for the first time.