Consumers who wanted to apply a full federal tax credit to buying a $35,000 Tesla Model 3 sedan appear to be out of luck.

The electric-car maker said on its website that orders placed by Monday will be delivered by the end of 2018 and therefore are eligible for the full $7,500 federal tax credit. Under rules set by the Internal Revenue Service, they will only get a credit half as large starting next year because Tesla has sold more than 200,000 vehicles in the U.S. Eventually the credit will disappear altogether.

But...