We may not have interplanetary travel for humans yet, but it's never too early to start dealing with problems related to interstellar trade and solar system stock market crashes. That's why textbook publisher Routledge has a journal called Astropolitics, whose latest issue features an in-depth scholarly article on "problems of interplanetary and interstellar trade." And no, the problems aren't "we don't have warp drive yet."
International Studies professor John Hickman sums up his article thusly:
If and when interplanetary and interstellar trade develops, it will be novel in two respects. First, the distances and time spans involved will reduce all or nearly all trade to the exchange of intangible goods. That threatens the possibility of conducting business in a genuinely common currency and of enforcing debt agreements incurred by governments. Second, interstellar trade suggests trade between humans and aliens. Cultural distance is a probable obstacle to initiating and sustaining such trade. Such exchange also threatens the release of new and dangerous memes.