Shares tumble 10% after 27% fall in revenues forces $749m write-off in exploration costs and $406m write-down in assets
Exploration company Tullow Oil has promised to its cut costs further after posting a $1bn (£690m) pre-tax loss, blaming rock-bottom oil prices.
Revenues fell 27% to $1.6bn, forcing Tullow to write off $749m in exploration costs and slash the value of equipment and property by $406m.