Bain Capital and several other private equity firms had also looked at the business — owned by Canadian buyout shop Onex — but they are no longer involved as the auction has reached a final stage, two of the sources said.

Onex, which bought Husky for nearly $1 billion in 2007, has been working with JPMorgan Chase and Goldman Sachs Group on a potential sale or initial public offering for the company, which makes machines used to manufacture plastic products like bottles and cutlery.

All of the sources declined to be named because the process is not public.

Bolton, Ontario-based Husky, founded in 1953, is one of the world's largest suppliers of injection molding equipment and services to the plastics industry. Its products are used to make products such as bottles and caps for beverages, containers for food, medical components and consumer electronic parts.

Husky posted revenue of $1.1 billion in 2010, according to Onex's website. It had earnings before interest, taxes, depreciation and amortization (EBITDA) of $197 million in the year ended Sept. 30.

A deal to buy Husky would be a large transaction for Berkshire Partners, which typically does deals between $200 million and $2 billion, according to its website. Berkshire has raised $6.5 billion of private equity capital since 1984 through seven investment funds.

Over the past year, there has been a flurry of secondary buyouts — when private equity firms sell assets to rival buyout firms — as firms are under pressure to invest billions of dollars raised in 2006 to 2008.

Representatives for Berkshire, Onex and Goldman Sachs could not be immediately reached for comment. JPMorgan Chase declined to comment.