Podcast publisher Wondery Inc. has raised $10 million in funding as it seeks to add to its slate of original programs and expand globally. The new round of cash, which quintuples the largest independent podcasting company’s valuation from last March, “is the latest sign of explosive growth in the nascent podcasting business,” The Wall Street Journal reports.

For background, podcast advertising revenue in the U.S. grew 53% last year to $479.1 million, higher than an earlier forecast of $402 million from the Interactive Advertising Bureau and PricewaterhouseCoopers. Revenue is expected to grow another 42% this year to $678.7 million and top $1 billion by 2021, the Journal story explains. Last year, for the first time, more than 50% of the U.S. population 12+ tuned to a podcast, according to Edison Research.

“Podcasts are growing faster than anybody expected, both from total listening as well as total advertising revenue,” said Wondery CEO Hernan Lopez.

The investment will be aimed at expanding Wondery’s programming offerings with shows in multiple languages and production of daily podcasts. The company also hired TV and digital-media veteran Declan Moore, most recently CEO of National Geographic Partners, to lead global efforts.

Wondery hit $10 million in revenue last year, the Journal reports, and became profitable in Q4. It is on track to reap $25 million in revenue this year, and expects to turn an annual profit. The company is the fourth-largest podcast publisher in the U.S. by audience, behind National Public Radio, iHeartRadio and PRX, according to Podtrac. It currently offers 66 active shows, including the No. 1 and No. 2 top new shows of 2018, “Dr. Death” and “Gladiator: Aaron Hernandez and Football, Inc.” Wondery’s popular true-crime podcast “Dirty John,” which had more than 8 million downloads per episode, was turned into a television series for Bravo and Netflix, as Podcast News Daily reported earlier this month. In addition, series “Gladiator” and “Over My Dead Body,” were optioned for TV by Walt Disney’s FX and WarnerMedia, respectively, while NBCUniversal has optioned “Dr. Death,” “The Vanished” and “The Wonderland Murders by Hollywood & Crime.” Further, in April, Wondery struck a deal with Vivendi SA’s Universal Music Group to develop original podcasts based on its musical catalog and roster of artists and labels.