By Mark Gongloff

We wrote earlier about what's ailing Bank of America, still the worst stock in the S&P 500. Add one more log to the pyre.

Corrie Driebusch and Caitlin Nish write:

China Construction Bank said BofA will keep a 5% stake in CCB,compared to the 10% stake BofA holds. Many analysts expected Bank of America toquickly look to sell the entire stake when it was able to after this month.

The worry is that, if BofA keeps some part of CCB, it will be more likely to need to raise capital down the line.

Bloomberg adds:

Some analysts, including Charles Peabody of Portales Partners LLC, had estimated the Charlotte, North Carolina-based bank would divest all of its shares.

"People like me thought they were going to unload the whole thing to help build their capital," Peabody said in an interview. "It means the process of getting to their Basel 3 capital goals could be more elongated, or that they will be more dependent upon increasing their disposition of non-core assets." The latter could further pinch revenue, he said.

Bank of America Chief Executive Officer Brian T. Moynihan, 51, has been selling businesses and assets as the firm seeks to comply with new international capital standards set by the Basel Committee on Banking Supervision. Last week the company announced it was exiting credit-card markets outside the U.S., and Moynihan said the lender will continue to pursue such sales.

As Bloomberg notes, BofA's stake in CCB is worth nearly $20 billion, which would go a long way toward plugging whatever capital holes BofA has.

At last check, BofA shares were down 6.3%, hanging just above the $6.50 level that some see as key support.