HBO has the most profitable iOS app by Victor Luckerson @FortuneMagazine June 25, 2015, 2:25 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Two months after its launch, HBO’s TWX new standalone streaming service seems to be bringing in a lot of money. HBO Now was the highest-grossing highest-grossing app globally on iOS in May, according to App Annie, a research firm that tracks app sales and downloads. At $14.99 per month, HBO Now costs significantly more than the typical apps people download. Still, the new service managed to top other streaming platforms such as Spotify and Hulu, which cost between $8 and $13 per month in the App Store. Right now, Apple AAPL devices are still the easiest way to access HBO Now without having it bundled with something else. Optimum CVC sells the service with its Internet package, and Sling TV offers it with a bundle of other channels delivered online. Soon Google GOOG is planning to launch the service on Android devices and Chromecast.