Details are still somewhat scarce, but it appears that Grisaia no Kajitsu‘s 2nd and 3rd Visual Novels have been green lit to become anime.
The sales numbers for Grisaia have yet to be posted publicly, maybe it was a decent success? I hope so, Grisaia was a well made anime by ecchi genre standards.
Really though, it doesn’t need to be a big mover of blu-rays to justify more seasons. The anime is basically high yield advertising for the eroge source material. It strengthens the brand further, and probably helps with merch sales too.
ANN’s wording of the news, including this tidbit: “The first episode will be a 60-minute special…” would seem to hint at these follow up anime being TV series as opposed to a brief OVA.
It is unclear who will handle production, though you would think 8 bit would have first dibs. The hour long premiere episode will air in March.