According to informed circles, financial investors are interested in the online broker FlatexDegiro AG.
Whether the Frankfurt-based company can be taken off the stock exchange is, as has been heard, already being checked from this side.
In view of the news on Wednesday, the Flatex share price went up by almost 21 percent at times.
The market value of the brokerage house thus rose to around 2 billion euros.
A company spokesman said Flatex was open to formal takeover bids.
But he didn't want to say more about it.
Jefferies analyst Martin Comtesse is not surprised by the interest in private equity and refers to the recent fall in prices.
Compared to the end of June, the shares had lost more than 45 percent of their value.
Investment companies are increasingly interested in retail brokers, says Comtesse.
In addition to financial investors, large US brokerage houses could also show interest in entering or expanding business with European small investors.
Flatex's competitors include Sweden's Nordnet, Swissquote Group Holding and Britain's Hargreaves Lansdown.
Flatex started in 2006.
The company had considered selling it in the past, but decided instead to take over Amsterdam-based competitor Degiro BV.
The aim was to create a "Charles Schwab" of Europe.