While AIG climbed about 8.8 percent this year through Tuesday’s close, the insurer still trades for less than 80 percent of book value, a measure of assets minus liabilities. Travelers Cos., the lone property-casualty insurer in the Dow Jones Industrial Average, trades for more than 1.4 times book value. AIG jumped 2.8 percent to $62.65 at 11:48 a.m., the most intraday since August.