Page 47 of Fannie Mae's 2024 Q1 10-Q form shows that they have a shortfall of $156B to the Adjusted Total Capital requirement of $106B. 25% of the $82B buffer adds another $21B to give the total shortfall to being able to pay dividends: $177B.
$121B of that could be made up in an instant if Treasury decides to cancel the seniors
and it could happen - the GOV could cancel the LP value of the SP equity
if done - then the shortfall is 177 minus 121 or 56Billion