The group, the American Legislative Exchange Council, or ALEC, is made up of a group of lawmakers and private sector officials and has become a lightning rod for political debate in recent months. Wal-Mart has been a member since 1993.
Liberal activists complain that ALEC, which has been around for nearly 40 years, improperly influences legislation around the country by allowing corporate leaders to develop model legislation alongside state lawmakers. They also point to some of the laws that ALEC has helped spread around the country, such as ID rules for voters and the so-called "Stand Your Ground" self-defense law that's at the center of the Florida case in which teenager Martin was killed.
For its part, ALEC has said that it is being unfairly targeted as part of a broader campaign against its conservative agenda. It also says efforts to tie it into the Martin case are unfair. In April it said it would it was eliminating its public safety task force that had dealt with the "Stand Your Ground" law and said it was refocusing those resources on economic matters.
Late Wednesday, Maggie Sans, Wal-Mart's vice president of public affairs and government relations, sent a letter to ALEC leaders saying it has previously expressed concern about ALEC's decision to weigh in on issues that "stray from its core mission 'to advance the Jeffersonian principles of free markets.' "
"We feel that the divide between these activities and our purpose as a business has become too wide," said Sans, who has served as ALEC's Secretary of the Private Enterprise board. "To that end, we are suspending our membership in ALEC."
Wal-Mart's decision follows several other companies' withdrawal from the group, including Amazon.com, Coca-Cola Co., Kraft Foods Inc., McDonald's Corp., PepsiCo Inc. and the Bill & Melinda Gates Foundation.
ALEC said in a statement it is "disappointed" in Wal-Mart's decision but understands "the unique pressures they are under."
"However, as we announced in April, ALEC is solely focused on limited government, free-market solutions in the states that create jobs and improve the economy," the statement read.
The decision came in the run-up to Wal-Mart's annual shareholder meeting at its Bentonville, Ark., headquarters on Friday.
Wal-Mart's shares rose $1.11 to $66.55 in midday trading.