GTA 5 LCN stock exchange not working

Are you using a pirated version of GTA 5? This is something that happens with pirated versions, info in the discussions on this Reddit thread on pirated GTA V stock issues.

Always buy ONLY 1 stock when you want to invest. It won't be there in your portfolio, but the second time it will be there. If you see it in your portfolio than you can safely buy more stock from the same company.

This does seem to be a common bug as seen in the GTA rockstar community, there does seem to be the occasional fix that buying a small number of shares that disappear means that it wont happen again, and some say that its avoidable by not using the escape key to quit the browser, however I am having difficulty finding any kind of official Rockstar support on the matter.

If you haven't already auto saved, you can go to your GAME settings >then go to LOAD GAME>then go to the last time you AUTO SAVED. If this puts you back to around 30 mil, then go to the debonair stock and only buy about 5 stocks, those will disappear, but after that you can invest in it all you want.

I had this issue too, I ended up buying 1 of the cheapest stock and lost it. Then I was able to buy stock and keep them.

It’s a bug but I found a way to get around it, quick save before purchase, by 1 share of whatever your buying, check portfolio it will be empty, then by how ever many you want the second purchase will appear, you will lose the single one you bought but not a big deal since it’s just 1 share :)