Originally published Tuesday, January 15, 2019 at 03:42p.m.

SAN FRANCISCO — Netflix is raising its U.S. prices by 13 to 18 percent, its biggest increase since the company launched its video streaming service 12 years ago.

Its most popular plan will see the largest hike, to $13 per month from $11. That option offers high-definition streaming on up to two different internet-connected devices simultaneously. Even at the higher price, that plan is still a few dollars cheaper than HBO, whose streaming service charges $15 per month.

The extra cash will help to pay for Netflix's huge investment in original shows and films and finance the heavy debt it has assumed to ward off rivals such as Amazon, Disney and AT&T.

While subscribers might bemoan a bigger monthly bill, Wall Street cheered, sending Netflix's shares up 6.5 percent Tuesday.

This marks the fourth time that Netflix has raised its U.S. prices; the last hike came in late 2017 . But this is the first time that higher prices will hit all 58 million U.S. subscribers, the number Netflix reported at the end of September.

Previously, Netflix had continued to offer a basic, $8-a-month streaming plan while raising rates on more comprehensive plans with better video quality and options to watch simultaneously on different devices.

This time, the price for the cheapest plan is going up to $9 per month. A premium plan offering ultra-high definition will jump to $16 per month from $14.

The new prices will immediately affect all new subscribers and then roll out to existing customers during the next three months. Customers in about 40 Latin America countries where Netflix bills in U.S. currency will also be affected, excepting key international markets such as Mexico and Brazil.

Netflix had nearly 79 million subscribers outside the U.S. as of September.