The FDICUS Government tries to get another bank to take over the failing bank before it completely collapsecollapses. That makes sure there money to makeIt avoids the depositors whole doesn'tsituation where the FDIC would have to come 100% fromcompletely replace the depositors money. The customers of the failing bank become customers of the combined bank. The FDIC only has to address any shortfalls.
Lets say the bank is worth $900 Million and the total deposits that are either under 250K or maxed out at 250K equals $875 million and the excess deposits are $25 Million. Then everybody is made whole.
Now lets say the bank is worth $900 Million and the deposits that are either under 250K or maxed out at 250K equals $975 million and the excess deposits are $25 Million. The FDIC kicks in $75 million, people who have excess deposits will lose money. When their account is moved to the new bank they will not have all their funds. In your case there will not be $300K there will be $250k.