HBO Now, Showtime OTT and Starz OTT are pulling in a great deal of their subscribers from Amazon Channels, and it means a big missed opportunity for them, according to BTIG analyst Rich Greenfield.

In a research note, Greenfield likened the services less as direct-to-consumer products and more as wholesale relationships. He said BTIG believes that half of HBO Now subs are coming via Amazon Prime Channels, upwards of 75% of Starz, with the vast majority of Showtime via Amazon and Hulu add-ons.

“While it is phenomenal that premium channels such as HBO, Showtime and Starz are adding paying subscribers, they are not building a direct-to-consumer relationship. Amazon controls the data, consumers are using Amazon’s apps and maybe worst of all, Amazon is learning what shows interest consumers the most and is building their own video service utilizing that data to compete with the third-party channels they offer,” Greenfield wrote.

He added that legacy programmers “simply do not have the stomach for the pain (cost) of acquiring subscribers and mitigating churn,” while Amazon can easily add subscriptions to its existing bundle.

RELATED: Amazon Channels expands into the U.K. and Germany

Earlier this year, HBO said that HBO Now has surpassed 2 million subscribers. CBS has been less transparent with Showtime OTT’s subscriber numbers but reports from earlier this year indicated that the service was close to 1.5 million subscribers.

Meanwhile, Starz has been upfront about attributing the growth of its OTT platform, which reached 1 million subs late last year, to its Amazon partnership.

“The third season of ‘Power’ established a Starz record for viewership, surpassing 7.3 million multiplatform viewers per episode, and helping nearly drive OTT subscriptions close to the 1 million mark,” said Starz CEO Chris Albrecht in a statement. “The strong performance of our Amazon and Starz app initiatives complements the Starz Networks business with core distributors.”

While Amazon Channels, Amazon’s subscription VOD hub for its Prime members, may be responsible for much of HBO’s, Starz’s and Showtime’s OTT growth, those services were not included in the program’s recent European expansion.

Amazon Channels available in the U.K. will include Discovery, Eurosport Player, ITV Hub+, hayu, MUBI, BFI Player, MGM, Hopster, Shudder and Heera, Amazon’s recently launched Bollywood channel. In Germany and Austria, Amazon Channels will make available Arthouse CNMA, E! Entertainment HD, Kixi Select, MGM, MUBI, sportsdigital HD, Studio Universal Classics and Syfy Horror.