From the handy summary by RationalRevolution:
Jeb Bush defaulted on a $4.56 million loan from Broward Federal Savings in Sunrise, Florida. After federal regulators closed the S&L, the office building that Jeb used the $4.56 million to finance was reappraised by the regulators at $500,000, which Bush and his partners paid. The taxpayers had to pay back the remaining 4 million plus dollars.
Source:
http://www.rationalrevolution.net/war/bush_family_and_the_s.htm
The New York Times has a more complete, and forgiving, IMO, report:
A Savings and Loan Bailout, and Bush's Son Jeb
By Jeff Gerth, Special To the New York Times
Oct. 14, 1990
After Jeb Bush, a son of the President, and a partner bought a Miami office building using money an associate had borrowed from a local savings and loan, the Federal Government wound up repaying most of the loan.
The savings institution became insolvent, and the Government paid more than $4 million to make good the loan as part of the bailout of the savings industry. Mr. Bush and his partner negotiated a settlement with regulators in which they repaid $505,000 and retained control of the building. While they still have a $7 million mortgage to pay on that property, the settlement with the Government lifted from their backs a $4.565 million second mortgage.
There is no evidence that Mr. Bush or his partner improperly influenced the settlement process. Mr. Bush, in an interview, said he was a ''victim of circumstance'' and had no involvement in the settlement talks.
Mr. Bush invited a reporter to come to Miami to review the partnership's records. ''We have nothing to fear or hide about the transaction,'' he said.
Continues
https://www.nytimes.com/1990/10/14/us/a-savings-and-loan-bailout-and-bush-s-son-jeb.html
Deregulated S&Ls became opportunities for legalized fraud for the selected few.