These companies are paying closest attention to Trump's tweets

Simon Dawson | Bloomberg | Getty Images

President-elect Donald Trump's threats to selectively penalize U.S. manufacturers for moving production offshore may be difficult to enforce.

But for companies that depend on the U.S. government for a big chunk of revenues, his Twitter rants are hard to ignore.

"General Motors is sending Mexican made model of Chevy Cruze to U.S. car dealers-tax free across border. Make in U.S.A. or pay big border tax!" Trump said in a post on Twitter on Tuesday.

In response, GM said it makes its Cruze sedan in the United States and that all of those sold in the United States are made in a plant in Lordstown, Ohio.

"GM builds the Chevrolet Cruze hatchback for global markets in Mexico, with a small number sold in the U.S." the company said in a statement.

GM imports only hatchback versions of the Cruze from a factory in Ramos Arizpe, Mexico, and it sold only about 4,500 of them in the U.S. last year, spokesman Patrick Morrissey told The Associated Press. The company sold about 172,000 Cruzes through November. The hatchback, which went on sale in the U.S. in the fall, is built in Mexico for global distribution, Morrissey said.

The Trump tweet was another in a series of threats to slap a tax on companies that move production to Mexico and ship products back to the U.S. under the North American Free Trade Agreement.

Last year, Trump and Vice President-elect Mike Pence engineered a deal to keep 800 jobs at the Carrier furnace factory in Indianapolis from going to Mexico. Trump has also taken Ford to task for plans to shift production of the compact Focus to Mexico, even though the Detroit-area factory that now makes Focuses will continue to make pickups and SUVs.

On Tuesday, Ford announced that it will cancel production of a $1.6 billion plant in Mexico, and will instead invest $700 million in Flat Rock, Michigan.

Trump's other targets have included, Boeing and Macy's.

It remains to be seen whether Trump can selectively penalize individual companies with higher taxes. As part of a broader corporate tax reform, he has also proposed tax penalties for companies that move production offshore. Such a move would face opposition from many industries.

Regardless of how his new administration makes good on those threats, companies that rely heavily on federal contracts will remain leery of getting off on the wrong foot with the new administration.

In the 2015 fiscal year, for example, General Motors generated more than $236 million in sales to the federal government, according to the General Service Administration.

That's just a small fraction of the company's $152 billion in 2015 global revenues. But it's a big enough chunk of business to help ensure that Trump has the company's attention.

GM isn't even on the list of top 100 federal contractors, according to GSA data. Those companies are even more likely to follow Trump closely on Twitter.

While thousands of companies from dozens of industries do business with the federal government every year, the biggest contracts go to defense and health-care companies.