The London Stock Exchange on Friday rejected an unsolicited $37 billion takeover offer from its Hong Kong counterpart, saying that Hong Kong officials’ assertion that cementing the deal would be swift and certain was “simply not credible.”

London officials said in a letter to the Hong Kong Stock Exchange that they had fundamental concerns about the proposal, adding that the Hong Kong exchange’s relationship with the territorial government there would “complicate matters.”

“The board unanimously rejects the conditional proposal and, given its fundamental flaws, sees no merit in further engagement,” the London exchange said in a statement.

Stock exchanges have become national symbols of capitalistic clout, and a combination of the two would create a juggernaut to rival the leading United States exchanges. The proposed Hong Kong takeover was the latest move in a decade-long push to consolidate stock exchanges around the world, as new technology threatens to render traditional exchanges obsolete.