As part of the coronavirus stimulus action, the Fed bought $250 billion worth of mortgage-backed securities in a space of two weeks. For perspective, that dwarfs the amount they bought during the housing crisis by $80 billion.
Now mortgage bankers face bankruptcy

By flooding the market with money, the Fed forced down rates. Problem is, that just blew up the hedge.

Mortgage bankers are now getting margin calls and need to pay tens of millions of dollars to meet them. Even well capitalised lenders are on the brink of going under because of it.