LONDON (AP) — Shares in Provident Financial, a British sub-prime lender, have more than halved after the company's chief executive Peter Crook announced he was leaving with immediate effect following another profit warning.

In early London trading Tuesday, Provident Financial's share price plunged 63 percent to 6.40 pounds, meaning the company is not even worth 1 billion pounds ($1.29 billion) anymore.

It may not be the biggest of companies but its stock market retreat stands to be one of the biggest daily falls in the history of the FTSE 100 index of leading British shares.

Its fall from grace came as the company revealed a rapid deterioration in the outlook for its home credit business and scrapped its dividend.