system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokemon] Are all masterballs built by Sliph Co or have they been independently manufactured/discovered by other entities? Has the design improved in the decades since their invention or is the ball essentially the same still? Do they have any upper limits?
gpt
Yes Silph Co has the sole ownership and rights to produce master balls as we were the ones who invented it thou it is still in the devolpment stage of the product , but we unfortunately for the world ceased the production and testing of the master ball after the Team Rocket attack at Silph Co in Kanto. That's not to say there aren't any master balls period. It's just there are only a few and only in the hands of the most experienced and influential trainers such as Red the champion of Kanto. The ball is essentially the same over the decades as again Silph Co ceased any tests of them and stopped their production.  The upper limit of the master ball is basically none existent as it can catch Arceus or so it's been rumored as no one owns an Arceus to verify the rumors. But it definitely wouldn't work on pokemon owned by other trainers like other Pokeballs made by Silph Co and ball makers like Kurt as that's a lawsuit waiting to happen. 

TLDR: Silph Co has sole rights to make master balls but don't anymore. The design hasn't improved. It's only likely limit is other trainers pokemon for obvious reasons.  We here at Silph Co hope you are pleased with our customer support. If our information was satisfactory please leave us a 5 star review.