With Donald J. Trump on the clock to secure a nearly half-billion-dollar bond in his civil fraud case, a New York appeals court appears to have handed the former president a lifeline on Monday, saying it would accept a far smaller bond of $175 million.

The ruling by a five-judge panel of appellate court judges was a crucial and unexpected victory for the former president, potentially staving off a looming financial disaster. Had the court denied his request — and had he failed to obtain the full bond — Mr. Trump risked of losing control over his bank accounts and, eventually, even some of his marquee properties.

For now, those dire outcomes might be on hold. If Mr. Trump obtains the smaller bond, it would prevent the New York attorney general’s office, which brought the case accusing him of fraudulently inflating his net worth, from collecting while Mr. Trump appeals the $454 million judgment imposed by a trial judge. The appeal could take months or longer to resolve.