Deutsche Börse's interest in the London Stock Exchange was not exactly a secret. Since early autumn there have been rumours in the market that Deutsche Börse would be back for its third attempt at a merger. Perhaps the only surprise was that the bid came before Christmas.

What are the differences with the German exchange's iX proposal in 2000? IX, a poorly constructed merger plan for the two exchanges, was presented to the market as a done deal. At the time, the LSE was not a public company; the shares were widely held; the regulatory differences between the UK and Germany, for issuers and investors alike, were vast; and, while the proposal made some strategic sense, it would have imposed very significant costs on market participants of all types and sizes.