In the weeks after Election Day, one of the biggest donors in the Democratic Party, the LinkedIn co-founder Reid Hoffman, has considered what would once have been unthinkable for a billionaire who often talks about his patriotism.

Leaving the United States.

Mr. Hoffman, who has spent hundreds of millions of dollars on politics over the last few years, has told friends and allies that he is weighing a move overseas, according to three people with knowledge of the talks who insisted on anonymity to discuss private conversations.

Mr. Hoffman, who declined to comment through a spokeswoman, has helped pay for some of the most aggressive private litigation against Donald J. Trump, and he is worried about retribution from a president who has promised to go after his political opponents, including major Democratic donors.

While Mr. Hoffman’s reaction is dramatic — and it’s unclear how much moving abroad would protect him or his assets from Mr. Trump’s wrath — he is hardly alone in a liberal big-money world still stunned by Vice President Kamala Harris’s defeat.

Several major donors or their advisers have privately floated the idea of moving abroad, while many others are squinting apprehensively at the future — or trying to shape it. Some are distributing memos meant to guide the postmortem analysis for Democrats, beginning to kick around ideas for new media companies or imploring their peers not to let liberal fund-raising dry up.

All of that agita and nervous energy congealed last week in the lobby of the Salamander Hotel in Washington, where the typically sedate biannual meeting of the Democracy Alliance, a network of major liberal donors, became a four-day group therapy session.