Fundnel, a Singaporean crowdfunding platform was assisting spaceX with a recent raise[1]. The minimum investment value is 250k on the website now but if I recall correctly it was as low as 50k a few months back.

[1] https://fundnel.com/investor/deal-feed/funded

Often in these sorts of scenarios you can find an investment fund that has a stake in the non-public company that you are interested in and invest in the company by proxy by investing in the fund.

Wow! Do you happen to know any reputable ones where it'd be possible to single out (as much as possible, probably not possible completely) the investment into SpaceX?

the issue would now be that you're investing in everything else in that fund.. i'd have to believe in the fund, not just SpaceX.

You could design a portfolio of short and long positions that exactly cancelled out everything else the fund had.

Good luck with that considering most if not all of the other investments would be private investments that would be difficult, if not impossible to replicate in public markets.

Maybe you could find a bunch of other funds with slightly different positions in the same companies, and then form a linear combination that cancelled out the differences.

You'd end up with an "error portfolio" that was somewhat random that you'd be investing in proportionally with your SpaceX investment.

If I started a few listed companies and bought carefully constructed portfolios of unlisted securities specifically so that this would be possible, I wonder if the SEC would get mad.

I smell a SaaS product…

I smell financial regulation. The secondary market is generally only available to accredited investors. If you're investing in a fund, that's one thing, but if a product is unwinding all of that to allow unsophisticated investors to essentially buy secondary stock in private companies, the SEC is going to have something to say about that.