TIAA-CREF, the largest U.S. retirement fund, sold $52.4 million worth of Coke stock because of concerns about the company's social responsibility.

The sale was prompted when KLD Research & Analytics removed Coke from its list of socially responsible companies. KLD based its decisions on a number of issues — labor and human rights issues in Colombia, environmental issues in India and the marketing of high-calorie drinks to children in the United States, said Karin Chamberlain, manager of KLD Indexes.

She acknowledged that Coke has taken steps to address such concerns but said the company is often reactive instead of proactive.

The 1.2 million shares sold were in a so-called social choice account, in which about 430,000 pension clients invest, according to TIAA-CREF spokeswoman Stephanie Cohen Glass. TIAA-CREF still holds Coke stock in other funds.

In recent years, Coke has been a target of activists, who claim the company was involved in the murder of a union organizer in Colombia and in other anti-union violence. Coke has adamantly denied these allegations.

Coke has also been accused of damaging water in India, another issue that the company has denied.

KLD's decision was promoted in a press release by activist Ray Rogers, who has organized many protests of Coke on college campuses.

On the obesity front, Chamberlain said Coke was too slow to take sugary soft drinks out of schools. The beverage industry, including Coke, announced earlier this year that it would remove full-calorie soft drinks from schools and would restrict the sale of other beverages.

"KLD never discussed their decision with us, and they left it to a misguided activist to announce their action," Coke said in a statement Tuesday. "The decision does not reflect the significant progress we have made on the issues cited by KLD. Socially responsible investing is a very important and serious activity. It must be based on hard facts and clear information, not innuendo and supposition."