Pushback is emerging among conservative Republicans over President Donald Trump's apparent support for the Export-Import Bank, an institution they have pilloried as a giveaway to big businesses.

The Ex-Im bank, as it's called, assists U.S. companies' overseas business by doing things such as guaranteeing loans for foreign buyers of U.S. products, or insuring transactions. The agency takes on credit risks that private companies, including banks, aren't willing to accept.

Republican Rep. Justin Amash of Michigan, a vocal critic of the bank, is maintaining his opposition, a spokesperson said Friday. Republican Sen. Mike Lee of Utah, who co-sponsored a bill with Amash to abolish the bank, also said Friday that it should be repealed. And the conservative advocacy group Heritage Action reiterated that it believes the bank should be dismantled. More than 90 lawmakers have previously opposed the bank, according to a list compiled by the group.

"The Export-Import Bank is little more than a corporate welfare agency," Heritage Action said in a statement Friday.

Supporters of Ex-Im point out that such banks exist in one form or another among most developed nations, and U.S. companies would be at a disadvantage without the bank when they're bidding against rivals from Europe, China and elsewhere for overseas deals.

Trump's position on the bank shifted over the course of his presidential campaign. Initially, he rejected the bank, calling it "excess baggage" in a 2015 interview with National Journal. But he later appeared to soften that stance and said last spring that he would make his position clear soon.