Lazard chief Bruce Wasserstein bought over $17.85m (€13.22m) worth of shares in the investment bank, just before the stock plunged to a 52-week low.

Wasserstein acquired the Lazard stock in big blocks ranging in size from 9,000 to 100,000 shares both for his own account and for a Wasserstein family trust. He bought the shares between Tuesday and yesterday, when Lazard's share price tumbled from $40.27 to a 52-week low of $34.72.