Finding stocks following performance of certain investor, like BRK.B for Warren Buffett

Remember that unless you participate in the actual fund that these individuals offer to the public, you will not get the same returns they will.

If you instead do something like, look at what Warren Buffett's fund bought/sold yesterday (or even 60 minutes ago), and buy/sell it yourself, you will face 2 obstacles to achieving their returns:

1. The timing difference will mean that the value of the stock purchased by Warren Buffett will be different for your purchase and for his purchase. Because these investors often buy large swathes of stock at once, this may create large variances for 2 reasons: (a) simply buying a large volume of a stock will naturally increase the price, as the lowest sell orders are taken up, and fewer willing sellers remain; and (b) many people (including institutional investors) may be watching what someone like Warren Buffett does, and will want to follow suit, chasing the same pricing problem.

2. You cannot buy multiple stocks as efficiently as a fund can. If Warren Buffett's fund holds, say, 50 stocks, and he trades 1 stock per day (I have absolutely no idea about what diversification exists within his fund), his per-share transaction costs will be quite low, due to share volume. Whereas for you to follow him, you would need 50 transactions upfront, + 1 per day. This may appear to be a small cost, but it could be substantial. Imagine if you wanted to invest 50k using this method - that's $1k for each of 50 companies. A $5 transaction fee would equal 1% of the value of each company invested ($5 to buy, and $5 to sell). How does that 1% compare to the management fee charged by the actual fund available to you? [note that in the 4 years since I posted this answer, the increasing prevalence of fee-less transactions on many platforms has greatly reduced this issue]

In short, if you feel that a particular investor has a sound strategy, I suggest that you consider investing with them directly, instead of attempting to recreate their portfolio.

A couple points, first you don't point out what investors you want to invest with, and second BRK.B does not track anything; it is just a very small slice of his entire holdings BRK.A minus the voting rights.

One solid way to go would be to buy BRK.B and also a tech ETF like QQQ, or XLK, ..or both.

Since the vast majority of fund managers/big investors run private entities, it's not possible to track their performance. It's possible to look at what they are holding (that's never real-time information) and emulate their performance.