I'm not sure it's the riskiest asset class.... high yielding debt during rising rates is pretty risky... mortgage backed securities aren't yielding double digits for no reason...anything in Venezuela or North Korea is pretty high risk... pharma with only one project is crazy risky... commodity exploration... import export in the middle east has gotten very risky.
But with these types of investments you have to have more than one pick, so if something crazy happens to your top pick you still have others to fall back on.