According to a user on Twitter:
In January 2016 JYP had approached WG and stated that due to the management levels they may not be able to provide properly to WG due to many staff joining TWICE when TWICE was formed. JYP had stated that they would compensate WG for the lack of management by giving them more earnings through their sales. There was an agreed plan around this time that during WG's 10th anniversary the group would "disband" and members would move onto their separate ways in Feb 2017. This agreement that was made in 2016 was based off of their Reboot album which didn't do as well as expected. However, with their comeback with "Why So Lonely" and the unexpected success, members of the Wonder Girls noticed that it would be a better idea to stay together as a group of four, and are now negotiating with JYP what they can do as Wonder Girls now have some leverage. In addition, one of the oldest and the youngest members of WG (Yeeun and Sunmi), have been making their own negotiations with other companies to find a new company that will be able to manage and sign all members of WG (to keep WG) if they do end up leaving JYP.
Source + translation
Source is reupload from original tweet, which was taken down. Can't find out where the OP got their info from, but knowing how Kpop works this is all very plausable. I hope the girls can make it work because WE NEED MORE MUSIC FROM THEM.