The deadline for first-round bids to be submitted to investment bank UBS is August 11.
The Reed Business Information division, which houses magazines such as New Scientist and Farmer's Weekly, is being sold by Reed because it wants to reduce its dependence on advertising revenue.
According to reports, Reed is willing to offer a loan of around £160m to the eventual buyer to ensure the division is offloaded.
A number of US private equity firms including Candover, Cinven, Permira, Advent International and Providence are also expected to express their interest.