Last year Western Digital presented the record-breaking 12 TB HGST Ultrastar He12 HDD. It had to be followed by the 14 TB model of the same series, however, we are still waiting for that. In the meanwhile, Toshiba is planning to release such a sample soon.
The 14 TB novelty is expected to be announced by the end of the year. Key specifications (like the platter count and the interface used) are not reported yet. We just may assume that the SATA standard will be applied.
Presumably, the specialty by Toshiba will be filled with helium, being seven times less dense, than air. This will greatly diminish turbulence, produced by platters rotation, power consumption and the inside temperature.
Unfortunately, the 14 TB estimated price is unveiled up to this time. And finally, we should note, that early in the year the Seagate company mentioned its intentions to manufacture the 18 TB HDD in a year and a half.