UK bookmaker William Hill has confirmed it is in talks over a possible joint offer for gambling firm Sportingbet.
William Hill, which has 2,300 High Street betting shops, is attempting to reach a deal to buy Sportingbet with the European gaming company GVC.
Shares in the target company rose 17% as market rumours about the deal circulated.
Sportingbet is based in Guernsey and has more than 2.5 million registered customers in 200 countries.
William Hill and GVC have until 16 October to announce a firm offer.
They are likely to split Sportingbet's operations between them, with William Hill taking the Australian and other locally licensed Sportingbet businesses.
Sportingbet makes 90% of its profits in Australia and has about a third of the country's online gambling market.
William Hill said in a statement: "William Hill and GVC note the recent share price movement of Sportingbet and confirm that they are in the preliminary stages of considering a possible joint offer for Sportingbet.
"William Hill and GVC have committed to work exclusively with each other in this regard."