Currys, a major electronics retailer, has rejected a takeover offer from US investment firm Elliott.
Currys, which operates more than 800 stores and employs 28,000 people worldwide, said the offer would value the business at around £700m.
But that offer “significantly undervalued” the company, Currys said.
Elliott has a reputation as an activist investor, meaning he goes after companies in order to take over them and change the way they operate.
In 2018, it acquired British bookstore chain Waterstones for an undisclosed sum.
Mr Elliott said he was currently considering whether to make a formal offer for Currys and needed to make a decision by March 16 under UK takeover regulations.
Like many high street businesses, Currys is suffering from declining sales as customers cut back on spending.
Last month, the company announced that underlying sales, which exclude the impact of store openings and closings, fell 3% during the key Christmas shopping period.
Nevertheless, cost-cutting measures have led Currys to raise its profit forecast for the current year.
However, Currys' share price has fallen by more than a third over the past year, closing at 47.08p on Friday, valuing the business at around £534m.
Currys said in a statement that its board reviewed the “unsolicited” proposal from Elliott and “concluded that it significantly undervalued the company and its prospects.”
As well as Currys stores in the UK and Ireland, the business also trades under the Elkjøp brand in the Nordic region.
In November last year, the company announced a deal to sell its Greek business, trading under the Kotsovolos brand, for £175m.