Onex, Canada's largest listed private equity firm, agreed to acquire SIG for up to 3.57 billion euros in November from Reynolds Group Holdings, which is backed by New Zealand's richest man, Graeme Hart. An additional 175 million euros is also payable depending on SIG’s financial performance in 2015 and 2016.

The debt financing backing the acquisition is expected to comprise 1.965 billion euros of leveraged loans and 700 million euros of high yield bonds, denominated in euros and dollars. There is also expected to be a revolving credit of around 300 million euros, the banking sources said.

The banks underwriting the financing are Bank of America Merrill Lynch, Barclays, Goldman Sachs, Nomura, RBC, Credit Agricole, Mizuho, Rabobank, RBS and UniCredit.

SIG, world's second largest maker of drink cartons, manufactures aseptic carton packaging that allows juices, milk, soups and sauces to be stored for a long period of time without refrigeration. The company has around 5,100 employees in 40 countries.

Onex and SIG were not immediately available to comment.

(Editing by Christopher Mangham)

By Claire Ruckin