** Insurance broker Brown & Brown's BRO.N shares rise 4.5% to $70 premarket

** BRO launches a $250 million accelerated share repurchase program with Bank of America BAC.N

** Program part of co's $1.5 billion share repurchase authorization announced in October

** Stocks of insurance brokers have struggled this year on concerns that AI tools could speed up disruption across the sector

** Of 19 brokerages tracking the stock, two rate it "buy" and 17 "hold"; median PT is $83 - data compiled by LSEG

** As of last close, BRO down 16% YTD