The U.S. electric vehicle market is growing, but not fast enough during the latest quarter to prevent unsold EVs from stacking up at some automakers' dealerships or to allow Tesla to avoid new price cuts, according to analysts and industry data.

Rising inventories and price-cutting could represent only a short-term pause in EV market growth. But they could be signals that boosting U.S. EV sales above the current 7% market share level will be more costly and difficult than expected, even with federal and state subsidies.

Automakers North America have billions of dollars in EV-related investments riding on how the next several quarters play out. If production of EVs continues to outpace demand, automakers will have to choose between slashing prices and profit margins, or slowing assembly lines.