WESTLAKE VILLAGE, Calif. — Weak demand for new large pickups, high gas prices, reduced new home construction, and an overall weaker U.S. economy, has pushed down the value of trucks and put more owners in an "upside down" situation, according to J.D. Power and Associates.

In the first 26 days of May, more than four out of every 10 large pickup trades have been upside down. The statistic reflects the worst negative equity situation of any segment in the industry and far above the year-ago results for the segment.

The three segments with the highest negative equity in May were large pickups, midsize sporty and large utility vehicles. All three segments increased in negative equity from the previous year.

On the other hand, the industry’s three lowest percentages of upside-down trades in May belonged to luxury categories. Those three segments were midsize premium crossovers, midsize premium sporty and large premium conventional. All three segments decreased in negative equity from the previous year.