Under SEC Rule 144, a 10% and greater holder is an "affiliate" and has "control securities". Insiders have the same restrictions. A holding period is normal, but there are other restrictions.
The Trading Volume Formula is in play here for Control Securities. For an OTC stock an affiliate can sell no more than 1% of the outstanding shares in any three-month period. That's pretty restrictive and should keep any 10% or + holder locked in. They obviously know this rule, so if they go to 10% we know they're thinking hold, not sell
Now....SHhhhhhhh...