Automakers have been working to divert limited supplies of microchips toward production of their most important, fastest-turning models. Some have been partially building vehicles and parking them until enough chips arrive; General Motors modified some pickups to go without certain modules.
But with no certain end to the chip issue on the horizon, automakers soon could exhaust solutions for mitigating the shortage.
"The name of the U.S. car market this year is going to be about stock, production, supply," Volkswagen of America CEO Scott Keogh said.
Inventories have fallen by 20,000 vehicles since mid-March and plunged to the lowest point since mid-January, according to Cox Automotive. Stockpiles industrywide are 21 percent lower than a year ago. GM's inventory is just half the size it was a year earlier.
"If we get this under control in Q2, we can still recover a lot of that volume that was potentially at risk. But if it continues to move beyond Q2 and gets into Q3, more of that volume is going to become unrecoverable. That's going to start putting more downward pressure on new-vehicle sales," said Kevin Roberts, director of industry insights and analytics at CarGurus.
Gains by Japanese and European automakers significantly outpaced those of the Detroit 3 in the first quarter. Most of the transplant companies either doubled or nearly doubled their March 2020 volume last month. Ford Motor Co.'s 26 percent jump was by far the smallest March gain among the seven companies that report monthly results. J.D. Power said the industry had its highest March volume since 2000.
For the first quarter, Toyota Motor North America and combined Hyundai and Kia sales jumped more than 20 percent, and American Honda's sales rose 16 percent. Toyota crept closer to GM's crown as the largest U.S. automaker, trailing by only 36,340 vehicles.
Stellantis achieved a 5.1 percent first-quarter gain, with its Ram pickup jumping ahead of the Chevrolet Silverado again by more than 24,000 vehicles. After the Ram beat the Silverado in 2019 for the first time, Chevy reclaimed second place last year.
In the second quarter, pickup inventory likely will be pinched further, said Tyson Jominy, vice president of data and analytics at J.D. Power.
"Pickup inventory is already constraining sales, and the recent plant closures will make it worse," said Jominy. "While the industry has mostly sidestepped the challenges of the microchip shortages to date, April and Q2 are very likely to show cracks in the recovery."
Light-duty pickups that sold in March had been waiting just 41 days for a buyer, down from 88 days to turn in March 2020 and 89 days in March 2019, according to J.D. Power. Midsize pickups took just 34 days to sell in March, compared with 80 in March 2020 and 67 in March 2019.
"We're going to have less inventory at the end of April than we have now, but our sales pace is going to be faster than our replacement pace," said Charlie Chesbrough, senior economist for Cox. "That's when we're going to start to see that some consumers may just decide to wait or buy something else as opposed to getting something that they don't want."
Fleet accounted for only 1 in 6 light vehicles sold in the first quarter, vs. nearly 1 in 4 last year, J.D. Power said.
GM's first-quarter fleet volume decreased 35 percent as deliveries to rental companies fell by more than half from a strong first quarter last year. GM has idled production at plants that build vehicles popular with fleets because of the chip shortage.
But as the coronavirus vaccines become more widely available and consumers begin to travel again, fleet business could grow, analysts say.
"At some point, fleet is going to want to have some orders filled, and they may not be able to," Chesbrough said. "There could be a competition for that inventory."
Fleet volume fell 58 percent in March for Hyundai Motor America, but Randy Parker, senior vice president of national sales, said the company continues to work with its fleet partners to meet demand even as the retail business strengthens and inventory continues to tighten.
"We've got relationships with the fleet companies, and we've got model year 2021 contracts that we still have to honor," Parker said. "But now, they are looking toward the future with model year 2022, so we're going to continue to work with our partners as best as we can. This semiconductor shortage is not going to be out there forever."
Larry P. Vellequette and Laurence Iliff contributed to this report.