US industrial conglomerate United Technologies is nearing a deal to buy a firm in a move that would form one of the world's largest aircraft equipment manufacturers, according to a report.

The company is working on a $20 billion purchase of Rockwell Collins, at a price of about $140 a share, and could finalize the agreement later this week, the Wall Street Journal reported.

The news pushed up share prices for both companies, with Rockwell Collins up nearly two percent, and United Technologies up 1.5 percent in midday trading.

A Rockwell Collins spokeswoman said the firm had no comment on the report. United Technologies did not respond to requests for comment.

United Technologies already owns Pratt & Whitney aircraft engines but sold the Sikorsky helicopters to Lockheed-Martin in 2015.

Rockwell Collins, based in Cedar Rapids, Iowa, manufactures electronic equipment for cockpits and cabins. Last year it acquired American group B/E Aerospace for $6.4 billion.

United Technologies has an annual turnover of around $58 billion and employs more than 200,000 people. Rockwell Collins has a turnover of $6 billion and employs 19,000 people.