During questions after his statement on Tuesday Mr Davis apparently said (HERE) that, "Britain will only agree to a transition phase if the 'final relationship' has been agreed" which some commentators have taken to mean that he expects a trade deal to have been agreed by March 2019 and will only commit to a transition phase then. This is described in the report as "highly dangerous" and no doubt business leaders will be even more anxious than they are.
Banks and businesses want certainty. They cannot afford to wait until March 28th 2019 to find we are leaving with no deal agreed and no transition period in place. If Davis means what he said (and admittedly this would be unusual for him) companies will be relocating in the first quarter of next year if not before.
Davis' position is totally irrational. Firstly, the government actually thinks a trade deal is possible by March 2019 although most people are highly sceptical. The details need to be settled in twelve months to allow for ratification and this would be a world record for any trade deal let alone a "deep and special partnership" as Mrs May has suggested, details of which remain a mystery. What they call a transition will in fact be an extension of the Article 50 negotiating period where talks continue in order to reach an agreement. In fact the way things are going our own cabinet may need another two years beyond 2019 to decide what it is they actually want.