Glass manufacturer Pilkington has had a preliminary takeover approach from Japan's Nippon Sheet Glass which may lead to a bid of about £2.1bn ($3.7bn).
Pilkington is a leading supplier to the UK car industry
Nippon, which already owns about 20% of Pilkington, said it may make a cash offer for the remaining shares but said discussions were at an early stage.
The St Helens-based firm, one of the world's largest glassmakers, was founded in 1826 and has 23,000 staff.
Pilkington shares surged 20% after it revealed details of the approach.
The company's financial position has improved in recent years, making it more attractive to would-be buyers.
Last year it raised its shareholder dividend for the first time in a decade after boosting profits and sales.
Established in 1918, Nippon manufactures glass for buildings, cars, trains and IT products.
"Nippon Sheet Glass Company confirms that it has made an approach to the board of Pilkington which may or may not lead to a cash offer for the Pilkington shares it does not already own," the company said in a statement to the London Stock Exchange.
Analysts have put a bid value of about £2.1bn on Pilkington.
Media reports have suggested that building firm Saint-Gobain, currently fighting a battle to buy British plasterboard maker BPB, is also interested in acquiring Pilkington.
However, any bid from the French firm would face scrutiny from the competition authorities.
Pilkington is a global manufacturer, with factories in 24 countries.
Its shares were up 26 pence, or 20.5%, at 152.75p by late afternoon.