Time was running out for Donald Trump to secure a bond covering the $454m loss for his recent fraud case loss on Monday, opening the way for New York’s attorney general to begin the long, slow process of seizing his assets.

The former president has until Monday to secure a bond covering the half-billion-dollar judgment against him while he appeals the decision. Trump must post collateral covering 120% of the judgment, according to court filings, a sum of more than $557m. Last week his lawyers said it was a “practical impossibility” for him to secure a bond of this size.

“A bond of this size is rarely if ever seen. In the unusual circumstance that a bond of this size is issued, it is provided to the largest public companies in the world, not to individuals or privately held businesses,” his lawyers argued.

Related: Trump claims to have ‘almost $500m in cash’ despite inability to pay bond

The attorney general, Letitia James, had made clear that she will seize Trump assets if the bond is not secured. On Friday her office filed judgments in Westchester county, north of New York City, home to Trump’s sprawling Seven Springs estate and golf course.

A judgment has already been entered in New York City, home to some of Trump’s most famous assets, including Trump Tower and 40 Wall Street.

The moves are the first step in a chain of events James will have to take to secure Trump assets. “It’s not going to be a piece of cake,” said Nikos Passas, a professor of criminology and criminal justice at Northeastern University.

Passas said that besides the obvious political issues and Trump’s attacks on the attorney general, James faced difficulties over the complex and opaque financial structure of Trump’s assets. “There may be a lot of debts she may or may not know about. She may have to file a subpoena for financial information,” said Passas.

Passas said Trump might look to reach a deal with bond guarantors that takes into account a potentially huge Friday windfall.

Trump added a potential $3bn to his assets on Friday when his Truth Social social network finalized a long-in-the-making stock-market listing. The investment vehicle that merged with Truth Social has become a “meme stock” – an investment that has attracted a cult-like and whose price seems out of proportion to the business fundamentals.

But that too may be a hard sell. “Meme stocks notoriously go up and down like crazy,” said Passas. “Whoever makes a decision to deal with Trump at this point will be making a political as well as a financial decision.”