NEW YORK (Reuters) - Comcast Corp's (>> Comcast Corporation) adjusted quarterly profit topped analyst estimates on Wednesday, helped by more high-speed internet customers and higher theme park revenue.

Excluding the impact of a $12.7 billion one-time benefit following the U.S. tax overhaul signed into law in December, earnings per share were 49 cents, beating analyst estimates of 47 cents per share.

The biggest U.S. cable operator also raised its quarterly dividend by 21 percent to 19 cents a share, and said it expects to buy back at least $5 billion of its stock this year.

Shares were up 1 percent at $42.78 in morning trading.

Still, Comcast lost 33,000 video customers in the quarter ended Dec. 31, compared to an addition of 80,000 last year. The company's video business has been pressured by consumers canceling cable packages in favor of cheaper streaming options from companies like Netflix Inc (>> Netflix).

And while it added broadband subscribers, analysts have questioned how much that business can continue to grow. Comcast added 350,000 high-speed internet customers in the quarter, compared with a gain of 385,000 the same period a year earlier.

Comcast Chief Executive Brian Roberts also said on the company's post-earnings conference call that the company ended 2017 with more than 380,000 customer lines for its mobile service, launched in May.

Asked about the company's interest in acquisitions, Roberts said, "We are always looking for ways to create more value for shareholders," adding that "there's nothing we feel that we have to acquire."

Revenue grew 4.2 percent to $21.92 billion from a year earlier, roughly in line with analyst expectations of $21.82 billion, according to Thomson Reuters I/B/E/S.

Net income attributable to Comcast rose to $15.0 billion, or $3.17 per share, for the quarter, from $2.3 billion, or 48 cents a share. The company was able to book a gain on its deferred tax bill thanks to recently lowered U.S. corporate tax rates.

Revenue rose 3.4 percent in the cable business, which includes video, internet and voice services.

NBCUniversal's revenue rose 3.9 percent in the quarter, helped by the segment's theme park business.

(Reporting by Anjali Athavaley; Editing by Meredith Mazzilli)

Stocks treated in this article : Comcast Corporation, Netflix, Twenty-First Century Fox