Borsa Italiana's decision to bid for Montetitoli, the Italian Central Securities Depository, has struck another blow to the horizontal model of trading advocated by the London Stock Exchange (LSE), Euronext and Euroclear.

The exchange's board unanimously approved last week a proposal to acquire Montetitoli. If the Borsa does make a bid, it would mean a move towards the vertical model of expansion espoused by Deutsche Börse, rather than the horizontal model preached by the LSE.