American Express Co. plans to offer five-year debt in two parts.

The biggest credit-card issuer by purchases intends to sell fixed- and floating-rate notes to repay $1 billion of 4.875 percent debt maturing July 15, the New York-based company said in a regulatory filing. The offering may price as soon as today, according to a person with knowledge of the offering who asked not to be identified because terms aren’t set.

American Express last sold dollar-denominated benchmark debt in January, when it offered $1.27 billion of 2.65 percent notes due December 2022 and $1.05 billion of 4.05 percent securities maturing December 2042.

Citigroup Inc., Goldman Sachs Group Inc., JPMorgan Chase & Co., and UBS AG are managing the offering, the filing shows. The new debt may be rated A3 by Moody’s Investors Service, the person said.

Benchmark sales are typically at least $500 million.