European markets have repeatedly moved on rumours about the health and funding needs of indebted euro zone governments, and more recently on some of its major banks, Reuters reported.
The DJ Stoxx index of European banking stocks has fallen 37 percent from a peak in February and touched a 28-month low on Thursday. The index is down 17 percent in August alone.
European regulators had previously played down the idea of a blanket ban on short-selling, through which an investor borrows shares and sells them on the expectation their price will fall and they can be bought back at a lower price.
EMSA said short-selling combined with rumour-mongering created a strategy that was "clearly abusive."
France will ban short selling on 11 financial stocks for 15 days, Spain will protect 16 stocks for 15 days, while Belgium will ban short selling of four financial stocks for an indefinite period. Details of the Italian ban were not immediately clear.
The European assault mirrors one by the U.S. Securities and Exchange Commission on Sept. 19, 2008, four days after Lehman Brothers collapsed, to temporarily ban short selling in 799 banks and other financial institutions.
The U.K. imposed a similar prohibition at that time.
The U.S. move was of questionable value, according to several academic studies. While share borrowing fell during the three-week ban, financial stocks continued to plummet.
It also raised philosophical issues about whether regulators should interfere with the free market and the rights of investors to hedge or speculate. The move was also criticized by at least one former SEC official as a political decision.
In Asia, South Korea banned short-selling in all listed stocks on Tuesday. It already had a rule in place prohibiting the shorting of financial stocks. Hong Kong is bringing in rules forcing investors to disclose short positions above a certain threshold to the market regulator.
Some hedge fund experts said the European ban would likely limit liquidity by shutting out some market participants.
FRAGILE FRENCH BANKS?
The latest market turmoil focused on speculation about French banks, which are heavily exposed to European countries at the centre of the region's debt crisis. Societe Generale, France's No. 2 lender, has especially been in the eye of the storm.
Those rumours sent shock waves through credit markets, pushing interbank borrowing rates higher and triggering a 3-month high of 4 billion euros in emergency overnight borrowing from the European Central Bank.
The turmoil drove up European banks' borrowing costs to levels not seen since the 2007-2009 global credit crisis and raised the question whether the difficulties may foretell a repeat of the crisis, when arteries of global finance seized up.
The signals from Europe also set off alarm bells in Asia. Banking sources told Reuters on Thursday that one bank in the region had cut credit lines to major French lenders, while five others were reviewing trades and counterparty risk.
Investors said the latest loss of confidence was a sign that few of the problems that brought bank lending to a halt last time around have really gone away.