A top lawyer at the European Court of Justice says continent-wide rules on short-selling are overreaching and should be thrown out.

In an opinion Thursday, the court's independent Advocate General, Niilo Jaaskinen, said the rules threatened to replace national decision-making on short-selling, where investors profit by betting that a stock or bond will lose value.

During the eurozone debt crisis, many blamed such speculation for instability in the financial markets and several countries imposed temporary restrictions on short-selling — most of which were not renewed after markets stabilized.

Britain brought the case against the EU-wide regulations, which went into effect in November 2012, and Thursday's opinion — though not binding — holds sway when judges issue a decision.