Investors are still positive about the Dollar's potential under a Trump presidency. They see his policies as positive for business (tax cuts), positive for the economy (increased spending on infrastructure) and positive for interest rates (as a result of higher government borrowing and rising inflation). However, with the Federal Reserve's rate increase done and dusted there was less urgency to chase the Dollar higher in the lead-up to Christmas. It did slightly better than average over the week but not by much, giving up a dozen ticks to the Euro and taking a cent and a quarter off Sterling.
Sterling lost ground for five days on the trot, taking last place on three of those occasions. Some of that loss was the result of profit-taking sales: the Pound remains one of the leaders over the last month. But the Brexit story did not help: the latest word on the matter is that the Prime Minister will not commit to giving parliament a vote on the divorce package when it is agreed.