Retail stockbroker Share plc has been the subject of a takeover approach by rival Interactive Investor Services.
The company, whose main business is The Share Centre, confirmed the move after its share price surged to its highest for almost four years.
Shares in the company rose 16% to 35.4p in trading on Friday.
Interactive Investor has until the end of the month to confirm whether it intends to make an offer for the business.
In a statement to the stock exchange, Share said: “The board can confirm that it has received a preliminary approach which may or may not lead to an offer being made for the company.
“There can be no certainty that an offer will be made for the company, nor as to the terms on which an offer may be made.”
Last month, The Share Centre agreed to acquire £750 million worth of assets and 20,000 customers, predominantly in investment trusts, from JP Morgan Asset Management.
The Share Centre also acquired 15,000 customer accounts from the administrators of Beaufort Securities last year.
The Buckinghamshire-based company was founded in 1991 by Gavin Oldham and provides stockbroking services for personal investors.
It floated on the AIM index of the London Stock exchange in 2008.
In January, Interactive Investor, which was launched in 1995, revealed its own long-term intention to float on the London Stock Exchange, following other competitors Hargreaves Lansdown and AJ Bell.
A deal would follow its acquisition of Alliance Trust Savings for £40 million in October 2018.