CNOOC shares drop most in a month

Production halt at largest offshore field to reduce company's oil output

HONG KONG - Shares of CNOOC Ltd, China's largest offshore energy explorer, had their biggest decline in a month in Hong Kong trading after oil leaks at a field operated by partner ConocoPhillips Co forced the company to cut its output estimate.

The stock fell 8.9 percent to HK$13.84 ($1.78) on Monday. CNOOC has dropped 24 percent this year, outpacing the 14 percent decline in the benchmark Hang Seng Index.