The US$15.6 billion 401(k) program of Wal-Mart Stores Inc is now considering the bids from retirement plan managers. The said plan has been administered by the Merrill Lynch unit of Bank of America for the last fifteen years according to three anonymous sources familiar with the situation.

The retailer based out of Bentonville, AK is now in discussion with the retirement division of Wells Fargo & Co about the management of the program. This is the largest private sector retirement plan in the United States according to the anonymous sources.

Even with the discussion with other banks, Bank of America is still under consideration but it was unclear if other plan providers were also under consideration.

Bank of America is the second largest US bank while Wells Fargo is the fourth largest US bank in terms of assets. For its part, Wal-Mart had declined to provide a comment on the matter.

The Wal-Mart accounts are smaller compared to other retirement accounts, the sheer size of the company makes it one of the most attractive funds to manage in the industry. Wal-Mart is the world's largest retailer with 1,2 million individual employees that form part  of the retirement plan. The average account size is US$15,000 according data obtained by Brightscope, the firm that tracks and rates retirement plans.