The European Union’s chief executive warned Switzerland on Tuesday that it needs to formally endorse a new partnership treaty before June 18 to be able to keep the Swiss stock exchange’s access to the bloc’s financial markets.

Axar.az reports citing Reuters.

In a letter to the Swiss president, European Commission President Jean-Claude Juncker said he was ready to clarify any doubts but that the November 2018 draft treaty “will not be renegotiated.”

The so-called equivalence treatment of the Swiss exchange under EU law expires at the end of June, but procedural reasons require the EU Commission to make a formal proposal for an extension by June 18, an EU diplomat told Reuters last week.