Mill Rock Packaging acquires Keystone Paper & Box

Mill Rock Packaging Partners LLC has acquired Keystone Paper & Box Co., a specialty packaging company that manufactures custom folding cartons for consumer markets including food and beverages, pharmaceuticals and health and beauty.

Mill Rock Packaging, formed by Mill Rock Capital in 2020, is a specialty packaging company focused on leading design, innovation and technology. The company’s fourth acquisition marks its expansion to the Eastern U.S.

Keystone’s leadership team has made a significant investment in Mill Rock Packaging, according to a news release, and management will remain with the company. Terms of the transaction were not disclosed.

Based in Windsor, Connecticut, Keystone was founded in 1944 and focuses on multi-SKU, design-intensive packaging solutions and related services, including product engineering, prototyping and production. Its state-of-the-art production facility has substantial capacity for growth, according to the release.

“I am very proud of what we’ve achieved at Keystone since our founding by my grandfather,” Jim Rutt, president of Keystone, said in the release. “Through our partnership with Mill Rock Packaging, our customers will gain access to high-quality production facilities in the Midwest and West Coast.”

The combined company will operate six production facilities.

“We welcome the customers, suppliers and associates of Keystone to Mill Rock Packaging,” Mill Rock Packaging Chief Executive Officer Allen Ennis said. “We look forward to accelerating growth across the platform with Keystone as our flagship East Coast production and service center, supported by continued investment into its team and capabilities.”

Alvarez & Marsal, White & Case LLP and FINNEA Group advised Mill Rock Packaging on the transaction. Ben Markens advised Keystone Paper & Box.

“This is a highly strategic transaction that enables us to serve our customers from coast to coast, fulfilling Mill Rock’s initial vision to create a national consumer packaging powerhouse,” Bob Feeser, Mill Rock Packaging vice chairman and Mill Rock Capital senior partner, said. “We are excited to work with the Keystone team to advance our vision of a unified, national specialty packaging growth platform.”