Offer your thoughts or opinion on the input financial query or topic using your financial background.

Are the sellers selling pre-IPO shares over these websites legitimate or fake?
I think you're right that these sites look so unprofessional that they aren't likely to be legitimate. However, even a very legitimate-looking site might be a fake designed to separate you from your money.  There is an entire underground industry devoted to this kind of fakery and some of them are adept at what they do.  So how can you tell? One place that you can consult is FINRA's BrokerCheck online service.  This might be the first of many checks you should undertake. Who is FINRA, you might ask?  "The Financial Industry Regulatory Authority (FINRA) is the largest independent regulator for all securities firms doing business in the United States." See here. My unprofessional guess is, even if a firm's line of business is to broker deals in private company shares, that if they're located in the U.S. or else dealing in U.S. securities then they'd still need to be registered with FINRA – note the "all securities firms" above. I was able to search BrokerCheck and find SecondMarket (the firm @duffbeer703 mentioned) listed as "Active" in the FINRA database. The entry also provides some information about the firm.  For instance, SecondMarket appears to also be registered with the S.E.C.. You should also note that SecondMarket links back to these authorities (refer to the footer of their site): "Member FINRA | MSRB | SIPC.  Registered with the SEC as an alternative trading system for trading in private company shares.  SEC 606 Info [...]" Any legitimate broker would want you to look them up with the authorities if you're unsure about their legitimacy. However, to undertake any such kind of deal, I'd still suggest more due diligence.  An accredited investor with serious money to invest ought to, if they are not already experts themselves on these things, hire a professional who is expert to provide counsel, help navigate the system, and avoid the frauds.