This is not secret. Buffett said before his receipt of investment success - he don't consider minor share (less then 10%), only major, and sure, his best consul

This is not secret. Buffett said before his receipt of investment success - he don't consider minor share (less then 10%), only major, and sure, his best consultants dive deep into specifics of invested entity. Sure, this is extremely time consuming, and this mean, such investment business could only have very few wards, but this is extremely effective. You may wonder, why such simple rules are not widely used, but in reality many humans are not serious investors, they just like to play games with real money.