LONDON (AP) — Tesco shares have dropped sharply after Britain’s largest retailer by revenue issued another profit warning and slashed its dividend to shareholders by 75 percent.

The supermarket giant says market conditions remained challenging, cutting its forecast for 2014-2015 trading profits to between 2.4 billion pounds ($3.9 billion) and 2.5 billion pounds. Forecasts had been for 3.3 billion pounds.

Tesco says Dave Lewis, most recently an executive at Unilever, would start his job as CEO on Monday, a month earlier than planned. The company says he will review “all aspects of the group in order to improve its competitive position.”

He replaces Philip Clarke, who struggled amid intense competition from retailers catering to customers hit by tough economic times.

Shares were down 4.7 percent to 234.85 pence Friday.

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