The share price of Fiserv Inc. fell Thursday after an analyst report speculated that Bank of America Corp. might move some of its online bill-payment operations in-house.

The Brookfield, Wis., core-processing vendor's stock price closed down 5% from Wednesday's closing price at $49.95.

Greg Smith, an analyst who follows Fiserv for Duncan-Williams Inc., wrote in a research note that B of A's bill payment contract is worth $150 million to $200 million in annual revenue for the Wisconsin company.

Fiserv executives have said B of A continues to discuss a move in-house as a possibility, according to Smith, with a likely scenario being a gradual transfer of certain operations away from the vendor.

B of A's current bill-payment contract with Fiserv expires in 2013. It would probably require the banking company to pay a "significant termination fee" to end the relationship before then, Smith wrote.

A Fiserv spokeswoman wrote in an e-mail that the terms of its B of A contract "have not changed."

B of A did not respond to requests for comment.

Fiserv acquired the B of A relationship in 2007 when it bought the online bill-pay provider CheckFree Corp. for $4.4 billion.