China’s protracted property downturn is eroding the stability sheets of the nation’s largest state banks as their unhealthy loans creep up.Financial institution of Communications Co. reported Wednesday that its property unhealthy mortgage ratio jumped to 4.99% on the finish of final 12 months from 2.8% a 12 months earlier. Whereas the stability of its overdue mortgages slipped, the particular point out loans for the section — a number one indicator of soured loans — jumped 23% to 9.88 billion yuan ($1.4 billion).