With its sales slowing and its stock price tumbling, Tesla Inc. slashed prices dramatically Jan. 13 on several versions of its electric vehicles, making some of its models eligible for a new federal tax credit that could help spur buyer interest.

The company dropped prices nearly 20% in the United States on some versions of the Model Y SUV, its top seller. That cut will make more versions of the Model Y eligible for a $7,500 electric vehicle tax credit that will be available through March. Tesla also reduced the base price of the Model 3, its least expensive model, by about 6%.

Far from pleasing investors, the sharp price cuts sent Tesla shares down nearly 3% in midday trading Jan. 13. Since the start of last year, the stock has plummeted more than 65%.