Direct share acquisitions are possible on IPOGO but typically only for large ($200K+) investment sizes. Secondary investments in private companies require much more legwork than your typical public stock transaction (for example on Fidelity or Charles Schwab). For one, every transaction must go through the company when shares change hands (imagine telling IBM or Microsoft every time you bought their shares). And the process requires providing specific language governing the transaction; each company's process is different. Finally, a number of documents must be compiled by the shareholder (a lot that shareholders don't even know about, which is why we made a shareholder checklist on our blog).