ALEXANDRIA, Va. — A day after describing in detail how millions of dollars in payments from Ukrainian oligarchs enabled Paul Manafort to live in luxury through 2014, federal prosecutors outlined on Thursday how his financial fortunes reversed so sharply in subsequent years that he made his Manhattan condominium available on Airbnb.

Witnesses for the prosecution in the fast-moving tax and fraud trial, which got underway on Tuesday, said Mr. Manafort, a former campaign chairman for President Trump, went from snapping up lizard- and ostrich-skin jackets worth at least $15,000 to skipping payments on more than $1.1 million in bills. His solution, they said, was to seek bank loans based on financial statements that falsely showed his debt-ridden political consultancy firm was awash in cash.

The testimony fleshed out how Mr. Manafort’s finances were altered by the loss of his main client, Viktor F. Yanukovych, the leader of Ukraine. Mr. Yanukovych was ousted from power in 2014 after a popular uprising and fled to Russia. Mr. Manafort, a veteran Republican operative and lobbyist, advised Mr. Yanukovych for a decade, earning tens of millions of dollars in fees.

By 2016, when he re-entered American politics by joining Mr. Trump’s campaign, his financial troubles had grown acute.