moua has entirely the correct read on this. I think it's great that you are trying to "go after spammers where they live", but you really should do your research first.
Well meaning or not, you didn't state that as an opinion, but rather as a fact, so you are well advised to have your ducks in a row. It is the height of ignorance to assume that spam touting a stock is in any way associated with the company whose stock is being touted. The SEC is all over that, and I'm sure they would love to see any evidence you have to support your claim that the company is involved.
No, I don't - at least on the basis of the information you have provided here. What makes you think that the spam is "from" the company? You've only established that a company that has a website has some spamming "pump and dump" manipulators touting their stock. The only evidence that is of value are the email headers, and most of those are forged (did you follow the confirmed IP addresses through the entire route?).
Where a site is hosted has nothing to do with the origin of spam referencing it, particularly with these kinds of "pump and dump stock market crooks. While it is a violation of DreamHost's Terms Of Service for a a user here to send, or cause to be sent, spam related to their site even using another mail service, the relevant issue here is complicity. Your casual observation that the spam touts a stock offered by a company hosted somewhere is no more evidence that they are complicit in that than it is that I own a red cat.
I that the point of your post here? - FUD designed to malign a webhost (and quite probably an innocent company) designed to feed on all of our hatred of spam and spammers. I call shenanigans!
On the outside chance that you are really well-meaning and just ignorant, I'll just say you should know something about what you are talking about before you make accusations. At the very least, report your "suspicions" to abuse.dreamhost.com or do a little technical research into the source of the spam before you go off half-cocked.