Bats, Nasdaq OMX and Nyse Euronext have all made offers for multilateral trading facility Chi-X Europe ahead of the deadline for a second round of bidding, according to press reports.
Chi-X Europe was launched in 2007 by Japan's Nomura through inter-agency broker Instinet, to take on traditional exchanges such as the LSE and Deutsche Börse in the wake of MiFID.
Instinet now has a 34% stake, with a group of 12 banks and trading firms - including Citi, Goldman Sachs, UBS and Citadel - holding the rest of the shares.
Since launch, the MTF has used faster trading technology and lower fees to attract market share from incumbents - it now attracts around a quarter of trading in FTSE 100 shares - and moved into profit this year.
In August the platform confirmed that it had received a bid enquiry, which was widely believed to have come from Bats, leading to it inviting approaches from others.
According to the Financial Times, Bats, Nasdaq OMX and Nyse Euronext have now made fresh bids, with a price of up to £300 million mooted.