All of the 12 regional Federal Home Loan Banks reported positive net income during the third quarter, reflecting fewer write-downs on mortgage-backed securities. The banks reported combined net income of $732 million for the quarter, compared to combined losses of $165 million one year ago, when five banks reported losses. The smallest gain came from the Seattle home-loan bank, which reported net income of $10 million, compared with a year-earlier loss of $94 million. The gain came as the bank wrote down its mortgage securities by $16 million, versus a year-earlier write-down of $130 million.