German engineering group Robert Bosch is considering a bid for U.S. appliances manufacturer Whirlpool, according to three people with knowledge of the matter, in a move that would further strengthen its position in the household appliances market.

Bosch has been talking to potential advisers about the possibility of making an offer for Whirlpool, which has a market capitalization of about $4.8 billion, one of the sources said.

The sources said it was not certain that an offer would be made and asked not to be identified because the matter is confidential.

Spokespeople for Bosch and Whirlpool said the companies do not comment on "market rumors." The U.S. company's shares jumped 20% in premarket trading after the Reuters report.

Buying one of the world's biggest white goods manufacturers would significantly beef up Bosch's home appliance business at a time when competition with Asian rivals is growing.

Whirlpool has been undergoing a major restructuring in recent years, which has seen it fold its European business into a new company controlled by Turkish rival Arçelik and divest its Middle Eastern and African businesses.

The potential takeover comes as Bosch, the world's biggest automotive supplier, is looking at acquisitions to grow its unit that manufactures large home appliances.

A deal for Whirlpool, whose brands include Ariston, Hotpoint, Ignis and Privileg, would rank amongst the biggest disclosed deals for the German industrial group.

Reuters reported in March that Bosch was among the industrial firms competing to acquire heating and ventilation assets worth over $6 billion from Johnson Controls International in the U.S.

Bosch CEO Stefan Hartung told German business daily Handelsblatt in May that the company was looking at a few bigger acquisition targets, and that it did not rule out entering a new business area or a global deal.

He told reporters earlier in June that the group was open to listing some of its divisions on the stock market as it explores financing options for deals. He did not say which divisions.

Whirlpool, a household name known for its large appliances such as washing machines and refrigerators, has in recent years been aiming to grow its customer base by expanding in smaller appliances such as espresso machines and other kitchen gadgets as it grapples with a slowdown in growth.

The Michigan-based company recently said it would cut about 1,000 jobs in a bid to boost profit margins.

Whirlpool has lost almost 50% of its market value over the past two years. Its Swedish rival Electrolux is down 35% in the same period.

Electrolux shares rose following the report and were trading up about 4.5% at 10:40 a.m. GMT.