LONDON Britain's TalkTalk (TALK.L) put the cost of last month's cyber attack at 30 million to 35 million pounds, and said it was too soon to gauge the impact on customer numbers, although it did see an immediate spike in defections.
Chief Executive Dido Harding said it had been a "challenging time" for the broadband company's 4 million customers.
"We obviously saw an immediate bounce in customers wishing to cancel their direct debits and to churn, but we saw those leading indicators come back down quite quickly," she said in an interview on Wednesday.
"The early signs are encouraging that we are doing the right thing."
Harding took to the airwaves to warn TalkTalk's customers that personal details, including bank account and credit card numbers, could have been stolen within hours of the attack on Oct. 21.
Only 157,000 customers were affected, it later said, but Harding had no regrets about going public so soon.
"When businesses do what's right for customers throughout they actually emerge much stronger as a result," she said.
Harding was positive about TalkTalk's prospects, and she said, notwithstanding the attack, earnings would rise in the second half.
"We are raising our interim dividend as we guided by 15 percent on the back of our confidence on the medium- and long-term trajectory of the business," she said.
"We expect to see a material step-up in EBITDA (earnings before interest, tax, depreciation and amortisation) in the second half and expect to grow the final dividend by 15 percent as well."
Shares in the company, which have lost a quarter of their value since the attack, were up 12 percent at 244 pence at 0852 GMT.
Analysts had said the company could scrap its interim dividend.
Barclays said there were "optimistic early indications of the impact of the cyber attack". It cut its estimate for full-year earnings to 275 million pounds from 300 million.
TalkTalk said revenue for the six months to Sept. 30 grew 4.7 percent to 912 million pounds, helped by customers taking more services like mobile and television.
Core earnings, however, fell 18 percent to 90 million pounds, and the company's broadband base fell by 80,000 after it disconnected 72,000 customers for non-payment.
(Editing by Sarah Young and Louise Heavens)