No. If your magic superweapon needs a small amount of red fairy dust and there is only one person making the red dust, it is a good idea to also buy some blue dust to conceal which type is the necessary ingredient. Nobody depresses any stock price, rather you give some false business to another source too.
Cold War business idea, half a century too late: manufacture a cheap, unremarkable substance and sell it at an extremely high price to the U.S. government, to confuse Soviet intelligence. Shroud the production in secrecy and compartmentalize knowledge of the manufacturing process, so that everybody involved in production thinks that in a different section of the plant something secret is being done to create an end product that is special and useful in some way, but in reality you're creating exactly the cheap, boring stuff you say you are. The government could drive truckloads of it into nuclear weapons production facilities, shuffle it around from one warehouse to another, and eventually relabel it as waste.
Putting a target on your back for some lucre
Woah IBM would be perfect for this kind of thing... :)
Sounds more or less like red mercury.
This certainly looks like good practice to me, but it could be undone by insider trading, which could ignore the blue dust supply chain. The article flirts with the possibility of there having been insider trading here, but does not seem to come to any definite conclusions. Given the weaker reporting rules of those days, it may be impossible to say.