Financial stocks still need the protection afforded by forcing short sellers to reveal their positions, the Financial Services Authority said on Monday, as it extended its disclosure regime indefinitely.

Under the rules, anyone with a short position equal to 0.25 per cent of the outstanding stock in one of 30 prescribed companies must publicly disclose their holdings. Short sellers aim to profit from share price falls and their secretive activities have been blamed – on scant evidence – for the sharp falls in financial stocks during the past year.