Banks have long complained the volume and speed of regulatory change is keeping them so busy that they have no time to focus on their day jobs. But, even by recent high standards, this week has been exceptional.

A few weeks after its publication banks are starting to come to terms with the more incendiary aspects of the Mifid II draft proposals and they are getting particularly animated about plans to regulate electronic trading.

Under the current proposals all firms trading in Europe must register with a European regulatory authority which could also require them to open an office in the region.

The banks are under no illusions what this would mean. Put simply, thousands of their US and Asian clients will stop trading in Europe, which will bad for the clients, the banks, Europe’s exchanges and the European market at large.

The banks are raising the alarm in the hope the proposals will be watered down or tinned altogether before the rules are fixed, perhaps in the early part of next year, but there is real concern this regulation could yet make the final cut.

The irony is, of course, that Europe is seeking to introduce a condition which has become a point of contention between it and the US, which has similarly draconian requirements around non-US firms.

And now the Securities and Exchange Commission (not the obvious protagonist as the regulator of the US stock markets) has waded into that debate, claiming non-US branches of US banks must be bound by the same rules as their parents.

Some US banks have sought to swerve Dodd-Frank by setting up subsidiaries in Europe to handle swaps trading on behalf of their non-US clients.

These units are legally and financially ring-fenced from their parent groups so should not drag their parents down if they got into trouble, which is the US government’s main concern.

But the SEC is taking no chances apparently and wants to extend the reach of Dodd-Frank to include these international units, potentially another blow to Europe’s financial institutions and markets.

Lastly, the US House of Representatives, where the Republicans hold the balance of power, has this week passed a new bill that offers US farmers and ranchers exemption from Dodd-Frank.

The world’s top banks will surely draw huge comfort from the fact that US rednecks are safe from Dodd-Frank but they could be forgiven for wondering when this regulatory maelstrom is going to end.

One firm that seems to be thriving in this new regulatory reality is the London Stock Exchange which this week unveiled its largest ever takeover.

The £1.6bn acquisition of Frank Russell, the US index and fund management firm, from its owner Northwestern Mutual is still subject to shareholder approval which will be established by a vote in September.

The deal looks like a good one for Xavier Rolet’s LSE as it takes the British exchange into the US and adds to its credentials as a global index provider.

The £1.6bn price tag looks good also based on the fundamentals and the LSE can expect to get some cash back when it sells the Russell asset management business.

The LSE said on Thursday it would undertake “a comprehensive review of Russell’s investment management business to determine its positioning and fit with the group”.

The British exchange is not saying it in so many words but the bottom line is the asset management business doesn’t “fit with the group” so they will look to spin it off at some stage and could raise as much as £700m for the sale, according to analysts.

Another bad week for the banks and another good week for the LSE.