On June 7, insurers that sell Medicare Advantage plans must submit their 2011 bids to the government. In a letter to four insurance-industry executives, Health and Human Services Secretary Kathleen Sebelius warned the companies not to increase premiums and co-payments for seniors. "Focus on price and quality rather than asking seniors who need healthcare the most to pay more for it," Sebelius wrote in a letter. The letters went to WellPoint Inc., Cigna Corp., BlueCross BlueShield Association and Health Care Service Corp., according to a person familiar with the situation. Those executives met with Sebelius last month.