The specific reason for the conference call wasn't disclosed in a statement the companies released Sunday.
"Walmart and American Express are committed to providing innovative financial services solutions to help consumers reduce costs and better manage their everyday finances," the two companies said.
The conference call begins at 8:30 a.m. EDT.
Zynga (ZNGA - Get Report), the social gaming company, saw its shares fall 12% to $2.48 on Friday after it forecast a loss for the third quarter and lowered its full-year outlook. For the full year, Zynga said it expects bookings between $1.085 billion and $1.1 billion, down from a previous range of $1.15 billion and $1.225 billion. "The change in outlook is primarily due to reduced expectations for certain Web games including The Ville, and delays in launching several new games," Zynga said in a statement last week. Apple, Zynga, Sourcefire: Tech Winners & Losers
General Motors (GM - Get Report) said it and its joint ventures in China sold 244,266 vehicles in the country in September, an increase of 1.7% from last year. Al Gore Walks Away From Green Energy
AngioDynamics (ANGO), the medical instruments maker, is expected by analysts Monday to post fiscal first-quarter earnings of 9 cents a share on revenue of $84.4 million.
-- Written by Joseph Woelfel
>To contact the writer of this article, click here: Joseph Woelfel