On February 5 the metal peaked at $7.90 an ounce when the investor disclosed he had spent $900m on silver over the past six months.
In response to dealers' demands the London Bullion Market extended the period for physical delivery from five to 15 days.
Silver reaches 10-year high
Silver prices reached their highest level for a decade last week when dealers learned that the American billionaire investor Warren Buffet had bought 20 per cent of the world's total supply.
