(Reuters) - Britain's main index see-sawed in to the black with StanChart surging to a 9-month high after a buyback plan, while restaurant group Whitbread and miner Glencore lost ground after weak forecasts.
The FTSE 100 index climbed 0.1 percent by 0709 GMT, but the FTSE 250 declined by 0.1 percent, dragged down by a near-20 percent drop in Sirius Minerals after announcing a discounted share sale.
London-listed shares in Standard Chartered jumped nearly 4 percent after the bank unveiled plans for a share buyback of up to $1 billion, its first such in at least 20 years, and posted higher earnings.
Those gains were offset by a 2.6 percent drop in Glencore as it cut its 2019 copper output target following severe flooding in Australia, and a 2 percent fall in Premier Inn owner Whitbread after forecasting weak room revenue growth in the UK.
DS Smith also slipped 2 percent after the packaging firm said financial performance for the year had continued in line with its expectations. "There were no fireworks in the pre-close," Jefferies analysts said.
Among midcaps, Sirius Minerals tanked 18.3 percent, and on course for its worst day in a year, after it set a price range of 15 to 18 pence per share to raise about $400 million, a discount to its Monday's closing price of 21.9 pence.
Pub-operator Greene King lost 5 percent, despite forecasting annual pre-tax profit above analysts' expectations.
"Although this is a good result, we think it will have largely been priced in given the weak comparable and the favourable Easter weather," JP Morgan analysts wrote of Greene King update.
(Reporting by Muvija M and Shashwat Awasthi in Bengaluru; Editing by Peter Graff)