"We move from three possible options - soft, hard and cliff edge - to two. Soft Brexit is now off the table," Stubb said.
May's speech outlines how the U.K. wants to exit the EU's single market, which allows for free movement of goods, services and people. By doing so, the U.K. hopes to better control the number of EU migrants entering its borders.
In case the EU and the U.K. cannot strike a trade deal, May said the UK would leave the union completely. "No deal for Britain is better than a bad deal for Britain," she told an audience in London.
However, there are many issues on the table that need answers. The U.K. and the EU have now to decide how to trade with one another, how to ensure equal rights for EU citizens who already leave in the U.K. and British expats who live in other UE countries. They also have to decide about a land border between Ireland and Northern Ireland.
Kathrin Muehlbronner, senior vice president and lead UK sovereign analyst at Moody's, said in an email: "It remains to be seen how far-reaching and comprehensive such a new agreement will turn out to be."
"In our current baseline scenario we have indeed assumed that the UK should be able to secure an agreement that preserves many advantages of the UK's current Single Market access. We will see how likely such an agreement will be, once negotiations get under way with the EU in April," she added.