London Stock Exchange (LSE) has confirmed merger talks with Germany's Deutsche Boerse, the BBC reported Tuesday.
Shares in the LSE soared 17% after it said it was in "detailed discussions" with the German company about a "merger of equals".
Both companies said all their key businesses would continue to operate under their current brand names.
It is the third time the LSE and Deutsche Boerse have tried to strike a deal, first in 2000 then in 2004-5.
Shares in Deutsche Boerse rose 7%.