The frenzy on virtual-currency markets has prompted the starkest warning yet from the European Union’s financial-services chief, who said that investors are at risk of losing everything.

EU Commissioner Valdis Dombrovskis asked the heads of the EU’s three financial supervisors in a letter to update their warnings to consumers “as a matter of urgency” in light of recent market developments.

“The developments relating to bitcoin and cryptocurrencies in recent weeks require our heightened attention,” Dombrovskis wrote in the letter. “While I acknowledge the important opportunities offered by blockchain technology and its various applications, the current market developments around bitcoin constitute the signs of a pricing bubble, even if – in terms of global volume – it remains at the moment within a small share of the financial markets.”

Dombrovskis also said that the EU should consider regulating virtual currencies more broadly. “Further work to assess and potentially improve the applicability of our regulatory framework to bitcoin and cryptocurrencies will be necessary, building on the work ESMA has already started in this are,” he said, referring to the Paris-based European Securities and Markets Authority.

The comments mark a new step for the commission, which so far restricted itself to saying it’s analysing the situation, without touting any regulatory measures to protect financial stability.