Some major Democratic donors have told the largest pro-Biden super PAC, Future Forward, that pledges worth roughly $90 million are now on hold if President Biden remains atop the ticket, according to two people who have been briefed on the conversations.

The frozen contributions include multiple eight-figure commitments, according to the two people, who spoke on the condition of anonymity given the sensitivity of the situation. The decision to withhold such enormous sums of money is one of the most concrete examples of the fallout from Mr. Biden’s poor debate performance at the end of June.

Future Forward declined to comment on any conversations with donors or the amounts of any pledged money being withheld. A Future Forward adviser would say only that the group expected contributors who had paused donations to return once the current uncertainty about the ticket was resolved.