Diversification is for people who don’t know what they are doing. It’s fine and reasonable, but betting big on something you have an edge on is far better. I bought AAPL in 2011 because it was clear they weren’t just an iPhone maker.
Betting big and sticking with what you know pays off.
2011... that was right around the time of their recent split, give/take 1-3 years. At that time, the gamble was already lost.. What I mean by that was that the stock price at that time would have been around $650 - $750/share before the 1-7 split. Because of that, you're riding the second bump of the stock, whereas the gamble to bet big on would have been around 8 years prior, when they were bleeding money and almost dead at under $1/share, while Intel, AMD, NVidia, Yahoo, and others were doing much better, right after the .com bust. The 2011-2013 range was when I told my father to jump in on AAPL, as that split brought them down to under $100/share, and that's when he jumped in.
But it definitely is a good idea to diversify, and that has nothing to do with if a person knows what they are doing. Case in point: everyone that knew what they were doing jumped on pets.com and were going to ride that stock to early retirement. Then the entire .com market collapsed, leaving those shareholders to work at Home Depot. Those same people then turned to ride Enron, Tyco, and MCI/WorldCom home. We see where those scandal got them. Meanwhile, those who diversified and got into more commodities like lumber and durables raked in the money while still in tech stocks were able to smooth out that hit from tech by raking in the money from lumber. When the housing bubble crashed, they were still in tech and rode that.
Not diversifying is the equivalent of running RAID 0 and having a huge music or movie collection stored on it; when it crashes, you have no backup to use to restore what you lost, and your array is completely gone, meaning all data you have is gone with no recovery. You should always have a backup solution ready should your primary one fails.
BL.