Shares? I haven't seen them yet. But some SCOs offer paying with BTC.
I have heard of some stock brokenrs that had the option to let people use their bitcoins to buy stocks from them. although I find it very weird because if you consider bitcoin as an investment you are going to be using it as a diversification to your portfolio which should contain stocks and bitcoin alongside each other not use one to buy the other.
What else would be possible? Maybe buy shares (stakes) in mining farms with BTC?
this is not possible unless with secret contracts worth large sums of money between the mining farm operators and individual investors that also happens with solid legal contracts.
anything else, like what you see online is a Ponzi scheme trying to scam people using the name of "mining farm".