HBO Now, the standalone online version of the premium TV channel, has gained about 800,000 paying subscribers since it launched in April, contributing significantly to the 2.7 million net new HBO customers last year.
The figure was revealed by HBO CEO Richard Plepler in a conference call following the release of parent Time Warner Inc.'s quarterly earnings results.
The gains didn't seem to wow investors, as Time Warner shares fell 3.5 percent to $61.02 in afternoon trading Wednesday.
Stifel analyst Benjamin Mogil said the 3.2 percent gain in HBO subscriber revenue was lower than the 4.7 percent rise that Wall Street expected.
Initially available for $15 a month only on Apple TV and other Apple devices, HBO Now has steadily rolled out to other platforms including Amazon, Roku, Google's Chromecast and certain smart TVs.
Plepler said the service has yet to be offered on two major More