OM, the technology firm and operator of the Stockholm stock exchange, has agreed to buy Hex, the Helsinki stock exchange, and has ousted its chief executive Per Larsson.

OM already owns 15.6% of Hex, and is paying Skr1.575bn (€172m) for the outstanding shares in Hex with OM shares. Hex shareholders will receive 2.5 new OM shares for each Hex share they hold. OM was advised by Lenner & Partners, the corporate finance boutique which advised OM on its failed hostile bid for the London Stock Exchange in August 2000 alongside Lazard. Hex was advised by Mandatum.