President Donald Trump is likely to alter his tariffs on the auto industry in a formal announcement as soon as Tuesday, according to a person familiar with the matter.

The changes are unequivocally good news for stocks. But the car companies won’t emerge entirely unscathed.

For starters, the president’s tariffs for the car business won’t stack on top of one another, according to the person. There are multiple tariffs in place: levies on steel and aluminum; duties related to stopping the flow of fentanyl from Mexico, Canada, and China; and a 10% base levy on nearly all countries as part of Trump’s so-called reciprocal tariffs. Then, beginning May 3, auto makers then face a 25% sectoral tariff on car imports and a 25% tariff on imported parts.

If all of them were stacked together, a display unit from China would face tariffs of over 170%. A leaf spring imported from Mexico faces a tariff of almost 80%.

That kind of burden is too high to be offset by short-term cost reductions or price increases. The most severe calculations from Wall Street suggest all profits could be wiped out for the industry. The math isn’t that difficult. Take General Motors: It is expected to record 2025 U.S. sales in the range of $120 billion, which should generate an operating income of about $10 billion based on current profitability. Tariffs, as they are currently proposed, could add anywhere from $20 billion to $40 billion to GM’s costs.

The president is also considering a rebate that starts at 3.75% of the value of a car and moves down over time to offset parts tariffs and give companies time to adjust, according to the person. That could mitigate up to 50% of the hit.

The Wall Street Journal reported earlier that Trump was considering reprieves for auto makers.

The new tariff structure takes some of the worst outcomes off the table. GM now might face total cost increases of $10 billion to $15 billion, which is still significant but isn’t $40 billion bad.

That could translate to a price increase of roughly $2,000 to $4,000 for a new vehicle, far lower than the $5,000 to $10,000 tariff-related hike that Wall Street sees under the stacked tariffs.

GM didn’t immediately respond to a request for comment. The company reports first-quarter earnings on Tuesday morning.

Coming into Tuesday trading, shares of GM, Ford Motor, and Stellantis are down 12%, 5%, and 32%, respectively, since the Nov. 5 presidential election. The S&P 500 is down about 4%.

Shares of parts suppliers Magna International and Lear are down 20% and 12%, respectively.

The automotive stocks should react positively on Tuesday, recapturing some of those losses. The stocks probably won’t recover all the gains until policies are stable and auto makers are able to tell investors what costs they can offset.