After reading through the main book, I was wondering with the law against Imperial Citizen's owning xeno's artifacts, is there a legal xeno artifact market? Could a Rogue trader set up a trade with the Ordo Xeno's, or with the Adeptus Mechanicus for a reduced profit?

Salcor

It's listed in Creatures Anethema that the ownership of Xeno's artifacts is actually a grey area in Imperial Law (at least for the powerful). Some items are outright forbidden (as they're tainted or risky or for some other reason), often by the Holy Ordo's (or Mechanicus), which almost always includes all weapons (even an Ork Choppa, with exceptions). Such object de art' is very popular in certain (particularly noble) circles, as the hint of risk (which does exist, both from the objects themselves and those who object to their posession) adds a frison of fear. The Adetus Mechanicus holds (some) exemptions for (some) objects for (some) of its (higher ranking) members to study and reverse engineer (though they sometimes ignore this and reasearch objects anyway), what is heresay for an Enginseer may be a holy calling for an Arch-Magos (or not). Certain other Imperial Bodies hold exemptions too.

It's worth noting that a Rogue Trader can do what she likes outside Imperial Space (legally) but must conform (somewhat) more whilst inside it. The same is not neccessarilly true of her clients though.

For very specific items, perhaps. You might be better off keeping such items for when you need to "turn them over for the good of the Empire" when you need to curry favour instead. So establishing a contact in either organization and then handing over the item in exchange for help on some other matter might be a good step within a larger endevour.

Also, just because the trade is illegal doesn't mean that Inquisitors or Magos aren't interested in buying it. Both have considerable power, and reason to want to research such matters. Of course, approaching such people about that sort of matter is a task of the utmost difficulty, undertaken at risk of one's life.

If you didn't see it, there are rules for setting up a (relatively) less risky illegal trade in the Endevours section.

It mentions in the Rogue Trader book that there is a "grey market" for xenos items passed off as curios or arecheotech "made by unknown hands".

It's like how in Utah you aren't allowed to have bars that serve alcohol, so there are a whole lot of "clubs" that have $5 membership fees for a night.

Xenos items are very sought by many Imperial groups/personage. But it is an illegal market with good prizes.

I think one of the better ways for a Rogue Trader to traffic in Xenos Artifacts would be through a middleman. Footfall is a great example, the Rogue Trader could foster relations with a Cold Trade broker whom he can sell his artifacts to, without having to worry about nosing around for a buyer, or even leaving the Expanse. He's got plenty of reason to be at Footfall to replenish crew and supplies, and it falls within the realm where his Charter protects him as well.

The Ordo Xenos and the AdMech would likely be the best parties to legally sell xeno artifacts to - er, "to relinquish them, as is the duty of every loyal imperial citizen, for an appropriate compensation for the troubles inherent in being associated with these items." Rogue Traders should be able to gain connections to high-ranking members of those capable of paying the amounts those items are worth.

"Try not to wear those shuriken pistols openly around the Astartes. They get... jumpy when they they see those things"

"Nah man these are old school Mechanicus shuriken pistols Mars pattern"

I guess the official answer is "It depends." It depends on the specific Inquisitor, and how powerful he is. Do they have a vast network? Perhaps a portion of the Inquisitor's organization is the studying, and cataloging xenos artifacts. Then he either keeps them for further study/destruction, or returns them to the Rogue Trader. Then the rogue trader can sell them as official inquisitionally sanctioned xeno's artifacts. Of course the Inquisitor would get a percentage of the proceeds. Is that radical.....probably borderline.

Salcor