Hulu is keeping its pedal to metal in the streaming TV race: The company said it ended 2018 with more than 25 million total subscribers, a net gain of 8 million for the year.

The 47% year-over-year growth in subscribers for 2018 gives Hulu more video customers than the U.S.’s biggest pay-TV providers — including Comcast, one of its owners. But that’s not purely apples-to-apples: Hulu does not break out how many of its subscribers are only on subscription video-on-demand plans versus how many have live TV packages (which include access to the SVOD content).

Meanwhile, in another data point intended to highlight its momentum, Hulu claims it grew ad revenue more than 45% in 2018, to nearly $1.5 billion, a company record.

However, Hulu isn’t profitable — and its losses have mounted as the streaming-TV provider invests more in technology and content. Hulu lost as much as $440 million during the third quarter of 2018, more than double a loss of $207 million a year earlier and up from a loss of $357 million in Q2, according to regulatory filings by Comcast and 21st Century Fox. (The parent companies do not disclose Hulu’s revenue.)

Hulu competes against SVOD players like Netflix — which has more than twice the U.S. streaming subscribers — and Amazon Prime Video as well as over-the-top live TV services, including DirecTV Now, Sling TV, and YouTube TV. To build up its base, Hulu has launched heavily discounted promos including one timed for Black Friday offering the SVOD plan with ads for $12 in the first year. So there’s a question of how many customers will roll off once their promotional pricing expires.

By continuing its aggressive investment, Hulu believes it can stand out from the streaming pack with a unique offering that blends live TV and a large on-demand selection, including exclusive and original series. According to the company, customers who subscribe to Hulu With Live TV spend around 50% of their time watching VOD or recorded programming. And the average time spent on Hulu per subscriber each month increased 20% in 2018 (although it didn’t provide actual figures for watch time).

“Consumers have spoken loudly about their desire for more choice and control in their TV experience,” Hulu CEO Randy Freer said in a statement. “They are seeing the enormous benefits of streaming, they’re deciding which content and brands are most important to them, and they’re choosing Hulu.”

But to keep Hulu growing — and to turn it into a profitable business — its parent companies will need to pump in more cash and likely sustain ongoing losses in the near future.

Going forward, that’s mostly going to fall to Disney. In 2019, Disney is set to take 60% ownership of Hulu, through its acquisition of 20th Century Fox assets including a 30% stake in the joint venture. Comcast is the other 30% owner; AT&T’s WarnerMedia owns the remaining 10% but is considering selling that stake. Disney CEO Bob Iger has told investors the strategy is to make Hulu its SVOD platform for adult-targeted premium programming, while Disney+ is aimed at kids and families. Iger also says Disney is looking to expand Hulu internationally.

While Hulu has boosted content spending, it doesn’t have a huge stable of breakout original hits. Its biggest is Golden Globe- and Emmy-winning “The Handmaid’s Tale”; in 2018, season 2 of the post-apocalyptic drama drew a 76% increase in total consumption compared with season 1, according to Hulu. “Castle Rock,” the the anthology horror series from Stephen King and J.J. Abrams, was Hulu’s highest-performing new original of 2018 (by both reach and consumption) and was the second-highest performing Hulu original overall last year behind only “The Handmaid’s Tale.” According to a Hulu rep, two other original series — “Marvel’s Runaways” and “Future Man” — also perform extremely well.

A big focus for Hulu remains licensing popular primetime TV shows. The SVOD service now carries over 85,000 episodes of TV shows, more than any U.S. streaming service, according to Hulu’s internal data and consulting firm Ampere Analysis.

Hulu’s current series lineup includes “The Good Doctor,” “Killing Eve,” “The Orville,” “Superstore” and “Grown-ish.” It also clinched deals to become the exclusive U.S. SVOD service for every season of series including “ER,” “Lost,” “King of the Hill,” “Family Guy,” “Bob’s Burgers,” “Living Single” and “Animaniacs.”

On the live-TV side, in 2018 Hulu launched Starz as its fourth premium content add-on (joining HBO, Cinemax and Showtime) and also added eight live Discovery networks and a new Spanish-language live TV add-on option, which includes ESPN Deportes, Universo, CNN En Español and History Channel En Español.

Over the past year, Hulu said it has “dramatically improved the stability and usability” of its live TV service. For example, it claimed that Hulu With Live TV reducing buffering by 90% over the last 12 months. Hulu also has introduced new features, like live game-start notifications and an enhanced channel guide.

The median age of Hulu viewers is 32, which is nearly 25 years younger than the average age of U.S. broadcast TV viewers, which is 56, per Nielsen. The average annual household income of Hulu customers in 2018 was $93,000, according to the company, citing comScore data.