Back in 2010, when what was then known as the Sundance Channel acquired the French-German mini-series “Carlos,” no one realized the impact a 5½-hour, multilingual program about the notorious 1970s terrorist Carlos the Jackal would have on programming executives.

Olivier Assayas’ film, which bowed at Cannes, went on to win the Golden Globe for miniseries or motion picture made for TV, and helped jump start an interest in subtitled product on the small screen and streaming services that has only grown year after year.

“The quality of foreign-language TV has improved so much in the last couple of years, and here at Sundance we recognized that early,” says Jan Diedrichsen, general manager of what is now known as SundanceTV. “TV is now a medium much more friendly to higher-quality talent. Everyone wants to use this platform for long form series to tell great stories. That’s true in the U.S. and the rest of the world.”

SundanceTV, which subsequently broadcast three other foreign-language series, isn’t alone. Just about every major streaming service and several other TV networks — including PBS and Viceland — have acquired subtitled series from a range of countries that includes Brazil, Japan, Italy, Mexico, Denmark, Iceland, France and South Korea. For the most part, these outlets pick up foreign-language product to plug programming holes, appeal to niche audiences, or in the case of a network like SundanceTV, as an exercise in branding. But even though some streaming services boast an enormous amount of foreign programming — Hulu offers more than 600 international series, including shows from English-language countries — these programs are watched by only a small percentage of the overall subscriber base.

For example, SundanceTV’s critically acclaimed Italian crime series “Gomorrah,” which returns for its second season this month in the U.S., was seen by a regular audience of 70,000-100,000 viewers, barely 20% of the viewership for “Hap and Leonard,” the channel’s top-rated original series. Or, as Lisa Holme, Hulu’s vice-president of content acquisitions, puts it, “For the most part, foreign-language series are a small share of Hulu’s business.”

Yet this has not stopped outlets from jumping feet first into the subtitled business. And even though this might seem counter-intuitive, given how limited the market is for foreign-language theatrical releases — the $3.5 million U.S. gross for 2016 breakout, “A Man Called Ove,” would probably fail to cover the cost of craft services on a “Transformers” film — experts emphasize that there are significant differences between the theatrical market and TV and streaming outlets.

“The foreign-language movies making it into the U.S. are more art house, whereas in TV what you see getting imported are the biggest, poppiest hits in those countries,” says Hulu’s Holme.

Like “Narcos,” a series about Colombian drug lord Pablo Escobar, which is a co-production between Spanish-language broadcaster Telemundo and Netflix. Or “Tres Veces Ana” (“The Three Sides of Ana”), a steamy Mexican telenovela that has been a hit for Hulu. And “Trapped,” an Icelandic noir about the search for a killer during a monster snowstorm that has aired on Viceland. Even PBS has dabbled in the foreign-language world with “The Bridge,” a bilingual French-English production about a dismembered body found on the Chunnel border between the two countries, which was itself based on a Danish-Swedish series that has been available on Hulu (and inspired an American-Mexican iteration for FX).

“Great stories do not need to be limited to the language in which they were first written, and often times adding subtitles or dubbing content gives a series that extra reach,” says Brad Beale, VP of worldwide television licensing for Amazon. The digital player recently licensed “Locked Up,” a serialized Spanish drama, and “You Are Wanted,” its first German-language original series. “The combination of local originals and licensed foreign content create a first class catalogue for our customers in all regions.”

These series and others indicate that it’s not so much the country of origin, but the genre, that determines popularity. Scandinavian noir, a huge favorite ever since “The Girl With the Dragon Tattoo” books and movies, still attracts a large viewership.

Telenovelas, now featuring higher production values and more action, are big with Spanish-speaking audiences in the U.S. and throughout Latin America. Netflix has also had success with “3%,” a Brazilian dystopian series in the YA mold. And Hulu has seen anime score with the 18-35 male market. “Naruto: Shippuden,” based on a manga series and available in both subtitled and English dubbed versions, is one of the top five shows on the service.

Shows make it to America in a variety of ways. “We have relationships with distributors, actors, talent, we have our ear on the ground,” says Diedrichsen, who notes it helps that SundanceTV is part of AMC networks, a company with a global reach.

Adds Holme: “There, fortunately, is a group of people who control rights to programming, and we are in constant communication about what is coming up, and we have our eyes and ear on the ground outside the U.S. We scour the world, look at press reviews. And we attend most of the big trade shows.”

Many of these outlets are also involved in co-production deals with foreign entities, or acquire series before they are broadcast in their native countries. “Deutschland 86,” for example, the sequel to SundanceTV’s critically acclaimed Cold War spy series “Deutschland 83” is being financed by Germany’s UFA Fiction, Amazon, SundanceTV, and FremantleMedia Intl., with U.S. airing rights going to SundanceTV, followed by streaming on Hulu. Amazon retains online video rights in Germany.

With an eye toward both regional and global markets, Netflix has invested nearly $2 billion in European productions, including licensing and co-productions involving more than 90 original series and movies in different development stages across the continent. Shows include “Dark,” a German mystery, and “Suburra,” an Italian crime thriller. All series are then available to Netflix subscribers worldwide.

Costs vary from project to project. “When you have an ownership model, you are taking more of the risk, but when it’s a co-production you are taking on less risk,” ” says Diedrichsen who will not discuss specific numbers.

Hulu’s Holme says cost depends to an extent on a show’s popularity in its native country, but also on “how popular it will be in the U.S. There’s always a subjective judgment.”

No matter what, this craze for all things subtitled may not be a fad. Competition for series has become more fierce as additional players enter the market, and the cachet of being on TV in the U.S. only adds to the feeding frenzy. Outlets also like the diversity of the audience for subtitled series, which ranges from cultists looking for the latest anime or Scandi noir to what Holme refers to as “treasure hunters” for high-end Euro shows who tend to be “more focused and like to recommend shows.”

And there’s this. “We see a consistency in the audiences and a passion in them,” says Diedrichsen. “For people watching these shows, reading the subtitles actually makes them more engaged. These shows cannot be watched while you’re folding the laundry, and that’s a terrific thing in terms of engagement.”