I don't have a link for this but basically this is what I've determined so far.

The Fed owns 7T in U.S. Treasury securities, federal agency debt securities, and mortgage-backed securities through a special provision that allows it to create money to buy these assets.

It actually owns more, but this is just the portion bought with made up money and not customer deposits.

For assets bought with made up money, the Fed and its member banks receives a dividend at a rate capped at 6%.

The Federal Reserve uses part of the interest income to cover operating expenses, which include salaries, facilities, and other operational costs. (7.7B for 2023)

In addition, member banks received approximately $2.1B in dividend payments in 2023.

Any left over interest goes back to the Treasury.

Debt Holder Breakdown of the full 33T of US debt:

• Federal Reserve: ~22% of total federal debt.

• Foreign Holders: ~22% of total federal debt.

• U.S. Government Accounts: ~18% of total federal debt.

• Domestic Private Investors: ~27% of total federal debt.

• State and Local Governments: ~3% of total federal debt.

In summary, the Federal reserve profits greatly from buying up treasuries and other assets with made up money. This money goes to private member banks.