Risk management as an individual investor is totally up to your...

Risk management as an individual investor is totally up to your preference. If you can stomach the volatility of your portfolio rising and falling by +-10% in a day, you can do what Charlie Munger does and find companies that are certain to go up and bet large.

Charlies portfolio is made up of 4 stocks
1. Wells Fargo (52% of portfolio)
2. Bank of America Corp (43% of portfolio)
3. US Bancorp (4.5% of portfolio)
4. POSCO (0.5% of portfolio)

Risk Management incorporates more than the size of your investments relative to your portfolio.
It can include be performing all the necessary investment checks to validate if the company will rise in price.
Mohnish Pabrai has a video where he talks about his investment in Fiat Chrysler taking up 60% of his portfolio. He says that just because an initial 20% of his portfolio now takes up 60% doesn't mean he's going to readjust his portfolio because he still thinks its an amazing business and has more room for the price to climb.

Portfolio concentration is fine if it suits your investment style and you are near certain of the companies success. Its how Charlie Munger became a billionaire and how Mohnish Pabrai became a hundred millionaire.

Portfolio concentration is actually what I prefer.