The mailing giant will now be offering its customers equipment such as folding machines from Horizon and GAE's other kit manufacturers.
According to GAE, the deal will push its products into new areas, such as financial institutions.
The agreement further solidifies the relationship between Pitney Bowes and Japanese manufacturer Horizon.
Pitney Bowes recently bought Horizon's French supplier and has a close relationship with the company in Denmark.
Litho Supplies bought GAE earlier this year, therefore it is unlikely that Pitney Bowes would invest in the UK Horizon supplier.
GAE managing director Tony Hards said: "This move takes us into markets we don't currently enter into. More financial companies are looking to offering complete mailing and Pitney Bowes has seen that there is an opportunity to offer a more complete package."
Gareth Stoten, general manager for the UK & Ireland for Pitney Bowes, added: "This deal is further evidence of Pitney Bowes' growth and expansion and provides our customers with the necessary solutions and service-support to diversify and expand into new areas of business."
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