During the final Panty and Stocking staff webcast, series director Hiroyuki Imaishi has confirmed that a second season of Panty & Stocking with Gaterbelt is dependent on meeting Kadokawa’s expectations for merchandise sales as well as his personal desire to continue the series.
More info from /a/:
-Second season is, like the OST secret track said, up to Imaishi.
-The ending was indeed meant to set-up a second season.
-Panty and Stocking Nendroids coming.
-They can’t talk about Stocking’s final revelation yet but “Fallen Angel” probably holds some answers about it.
Translation of the important parts of the secret track (on the soundtrack):
Panty: Hey Stocking! I heard our anime Panty & Stocking with Garterbelt has got the green light for a sequel thanks to its popularity!
Stocking: What? Who the hell decided that?
Panty: Speaking of a sequel… how about a trilogy? Hell, let’s go further! We will reach season one hundred! A Hollywood remake is not a dream!
Stocking: Hey wait, Panty!
Panty: In fact, this planet is too small for us! Panty in the space! The whole universe will be calling my name!
Panty: So when will it start?
Stocking: How should I know, shitty hündin!
Panty: Coming up next, Panty & Stocking with Garterbelt Season two!
Stocking: Wait! I told you it hasn’t been decided yet! But, practically speaking, it’s up to director Imaishi now, right?
In other words, go buy the soundtrack.