Although the number of hybrid models in the U.S. continues to grow, few people who own one are sticking with the technology when they go to buy another car.
Only 35 percent of hybrid vehicle owners chose to buy another hybrid when they returned to the market in 2011, according to a study by R.L. Polk & Co., the automotive consulting firm. About 75,000 hybrid owners went new car shopping last year.
If you factor out the super-loyal Toyota Prius buyers, the repurchase rate drops to less than 25 percent.
Consumers in regions such as Southern California and Seattle, where hybrid sales are strongest, are no more likely to be repeat customers than buyers in other parts of the nation, according to the Polk study.
It's hard to know what's causing the low repurchase rate.
One factor could be trade-ins. About 17,000 people bought electric cars last year, and other data show that many of those were trading in a hybrid vehicle.
Another factor could be performance. Honda has been hit by a series of high-profile class-action and Small Claims Court lawsuits from customers alleging that older-model Civic hybrids weren't as fuel efficient as advertised.
Then there's competition and price. Online cross-shopping data from auto information company Edmunds.com shows that buyers typically compare hybrids with similar conventionally powered vehicles.
For example, the conventional Honda Civic is the second most cross-shopped car by people who also are looking at the Toyota Prius and Honda Insight hybrid models.
"The lineup of alternate-drive vehicles and their premium price points just aren't appealing enough to consumers to give the segment the momentum it once anticipated, especially given the growing strength of fuel economy among compact and midsize competitors," said Lacey Plache, Edmunds.com chief economist.
Even as they switch to gasoline-powered cars, hybrid owners tend to stay loyal to their auto brand.
Regular Honda Civics and Accords as well as straight gasoline-fueled Toyota Camrys and Highlanders "were the most popular sources of defection" for hybrid owners, said Brad Smith, a Polk consultant who directs the firm's loyalty practice.
Although the company has yet to research why hybrid owners aren't large repeat buyers, Smith said, the ever-growing choice of more fuel-efficient gasoline cars has to be whittling away at hybrids, which run on both electricity and gasoline.
Hybrid vehicles represent just 2.4 percent of the overall new vehicle market in the U.S., according to Polk, down from a high of 2.9 percent in 2008.
Toyota continues to lead the hybrid parade.
Its expanded Prius line, which now includes the "v" station wagon and the "c" subcompact, is selling well this year. Last year, Toyota sold 136,463 Priuses despite supply problems related to the Japanese earthquake.
No other hybrid was close. Ford, for example, sold only 11,286 Fusion hybrids.