Wind Point and Hearthside declined to comment on the announcement but Reuters claims the news was confirmed by anonymous sources.
According to its website, Hearthside produces baked foods and snacks from 20 factories in eight US states for the world's premier food companies, employing more than 7,500 staff.
Wind Point reportedly asked Barclays to run an auction for Hearthside, hoping to fetch more than $1bn.
The Downers Grove, Illinois-based company was created in 2009 by Wind Point and former Ralcorp Frozen Bakery Products President and ConAgra Foods Inc veteran Rich Scalise, who now serves as Hearthside's chairman and chief executive.
Hearthside started with four manufacturing plants and more than 2,000 employees and grew from acquisitions.
Last May it merged with another Wind Point company that specializes in food packaging, Ryt-way Industries, to create a food contract manufacturer with over $1bn in annual sales.
In May, Hearthside sold Golden Temple, its ready-to-eat cereals and granola making division, to Post Holdings, the company behind the Raisin Bran and Honey Bunches of Oats cereals, for $158m.