CNBC reports that with a new deadline of Sunday to decide on the future of Brexit trade talks, analysts closely following the negotiations say the chances of an agreement are quickly diminishing.

Mujtaba Rahman, managing director of Europe at Eurasia Group, said his team had reduced the probability of a deal from 60% to 55%.

Talks between the UK’s chief negotiator David Frost and his EU counterpart Michel Barnier will resume in Brussels Thursday. Key sticking points remain fishing rights and regulatory requirements, Raab noted Thursday, as well competition rules (the so-called “level playing field”) and governance of any deal.

If no deal is struck by Dec. 31, the U.K. will have to trade with the EU on World Trade Organization terms — which means import tariffs and higher costs of business for firms on both sides of the English Channel.

“Fundamentally, now, this is a dispute about the conditions the EU is setting to enter its market, and how the U.K. views these conditions. As it has very serious ‘across economy’ implications for the U.K., it’s very unclear whether Johnson will be able to agree,” Rahman said.