$比亚迪(SZ002594)$ $特斯拉(TSLA)$ Leasing companies buy new cars and arrange leases calculated on how much they believe they can sell them for at the end of the lease. Sudden drops in price undercut those residual values, costing leasing firms money.

There’s "nothing worse" than continuously dropping the value of a fleet buyer’s assets, said Richard Knubben, director general of Brussels-based Leaseurope, a leasing- and rental-industry group which represents national groups across 31 countries.

"Tesla is now actively telling our members: We can give you discounts and compensate you," Knubben said. "But Tesla's residuals have dropped so fast, I'm not sure the discounts they're offering are enough."

Chinese automakers including BYD are bringing lower-cost electric models to Europe and aggressively courting Tesla's corporate customers, according to fleet managers, along with executives from leasing firms. Legacy automakers such as Volkswagen and BMW are also producing increasingly competitive EVs.

National Grid has more than 500 Teslas in its company-car fleet of 2,000 vehicles. McAtear said she has planned to propose her company drop Tesla from its fleet unless the problems are addressed. Meanwhile, Tesla’s chief Chinese rival, BYD, is starting to deliver cars to National Grid.