Germany's temporary ban on naked short selling and naked CDS of euro-area government bonds is an attempt to shut down speculators, but the move is widely seen as likely to backfire. World markets slide and the euro hovers near four-year lows. DAX -2.2%, FTSE -2.1%, CAC 40 -2.5%, HSI -1.8%, Nikkei -0.5%. Euro at $1.221. S&P futures -0.8%.