Kaiser Permanente, the country’s largest nonprofit health insurer with 9 million clients and nearly $48-billion in annual revenue, will promote its president and chief operating officer, Bernard Tyson, to take the reins of the organization next year, Bloomberg reports. Mr. Tyson, a 28-year veteran of Kaiser, based in Oakland, Calif., will replace the chairman and chief executive officer George Halvorson, who is retiring at the end of 2013.