LONDON (Reuters) -Britain's Informa said on Wednesday it had reached a deal to buy Cannes Lions Festival owner Ascential for 1.2 billion pounds ($1.6 billion), adding the flagship ad industry conference to its portfolio of events.

Shares in Ascential, which also owns the Money20/20 fintech events, jumped 26% to 565 pence in early deals, just shy of the 568 pence per share cash offer.

Informa, which also upgraded its annual profit expectations, recovered early losses to trade broadly flat.

Informa said it would expand both events and accelerate growth, helped by its data platform and understanding of both the marketing and fintech sectors.

Informa Chief Executive Stephen A. Carter said both companies delivered double-digit growth in the first half of this year and were confident about their prospects.

"Powerful brands serving specialist markets are doing extremely well," he said in an interview.

"We're not buying this business for cost reduction, we're buying this business for growth."

Informa's offer is a 53% premium to Ascential's closing price of 371 pence on Monday.

Informa said the deal would boost adjusted earnings per share by at least 5% in the first full year, based on strong revenue growth and 12 million pounds of cost savings.

Citi analysts said the "fairly significant synergies" and the expected quick earnings boost would help assuage investors' concerns about the size of the deal.

"Net/net, we think this will be, if not well received, then certainly received more favourably than feared," they said.

Informa announced the deal alongside its first-half results that showed underlying operating profit growth of 18.8% and revenue growth of 11%.

It said annual adjusted operating profit would be above the top of current guidance, which stands at 970 million pounds, and could be up to 1 billion pounds.

($1 = 0.7756 pounds)