Donald J. Trump will exit the White House as a private citizen next month perched atop a pile of campaign cash unheard-of for an outgoing president, and with few legal limits on how he can spend it.

Deflated by a loss he has yet to acknowledge, Trump has cushioned the blow by coaxing huge sums of money from his loyal supporters — often under dubious pretenses — raising roughly $250 million since Election Day along with the national party.

More than $60 million of that sum has gone to a new political action committee, according to people familiar with the matter, which Trump will control after he leaves office. Those funds, which far exceed what previous outgoing presidents had at their disposal, provide him with tremendous flexibility for his post-presidential ambitions: He could use the money to quell rebel factions within the party, reward loyalists, fund his travels and rallies, hire staff, pay legal bills and even lay the groundwork for a far-from-certain 2024 run.