BankAtlantic Bancorp reported a narrower second-quarter loss Wednesday, trimming its loan write-offs from the first three months of the year. It lost $19.4 million, or 35 cents a share, in the quarter ended June 30, less than the $24.6 million loss of the first quarter. It earned $11.6 million in the second quarter of 2007. Home loan losses were a major factor in the swing to red from last year, management said. In an effort to isolate problem loans, it has moved $101.5 million in nonperforming loans to a newly created subsidiary of its parent company in exchange for $94.8 million in cash.