Shares in London-based oil explorer Tullow Oil jumped 7 percent after positive comments in research notes. One dealer cites a report from UBS which raises Tullow to 'buy' from 'neutral' based on valuation.
UBS says further exploration success could also make Tullow an M&A target.
The dealer adds Tullow shares are helped by brokers at other investment banks advising clients to buy the stock on Wednesday.
In another research note, RBC Capital markets says it expects Tullow's first half results next Wednesday to deliver 'good numbers and upbeat presentation'.
Tullow shares trade up 6.8 percent at 741 pence, outperforming a 2.2 percent rise in the DJ Stoxx European oil and gas sector index <.SXEP>.
