Well, there are only two highly controlled stocks - and the Russian’s play far better these days than they used to, so unlikely that any would be hidden. Thank G*d the Chinese don’t have fingers in this pie...
“Well, there are only two highly controlled stocks”
That are officially known about.
I would not be surprised if other governments, or even our own government, had a secret stockpile that you’d need a top level security clearance to even know about. Smallpox is one of the primary bioweapons that all countries with bioweapon programs studied, after all.