Electric vehicles could soon become even more expensive.

Under the House Republicans proposed tax bill, the $7,500 tax credit owners of electric vehicles can cash in on could disappear. Under current law, automakers can offer the $7,500 credit for the first 200,000 plug-in vehicles it sells. After that, the tax credit phases slowly out.

It's an important sales tactic for electric automakers including Tesla Inc. (TSLA) - Get Report , General Motors Co. (GM) - Get Report and Nissan Motor Co. (NSANY) . For example, a GM-made Chevrolet Bolt could cost $42,500 without the tax credit, whereas it costs a more affordable $35,000 with the credit.

The GOP's proposal is a stark deviation from the last administration's position on electric cars. Former President Barack Obama attempted to raise the tax credit for electric vehicles to as much as $10,000 and convert it to a point-of-sale rebate, but was continually rebuffed by Congress.

The proposed tax plan, of which a summary was made public Thursday, also suggests repealing or phasing out several other energy tax credits. Those include a credit on production and investment for solar, geothermal, fuel cell, wind energy and other green projects, plus a credit for residential energy-efficient projects.

Electric vehicles require expensive batteries that result in a heftier price tag than models with traditional combustible engines have. Without a tax credit, automakers might find it harder to make enough electric sales and meet the growing mandates from state governments to produce electric models.

In afternoon trading, Tesla stock slipped 7.43% to $297.22. GM shares dipped 0.93% to $42.73 and Nissan stock was down 0.15% to $19.49.

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