My original thought process for Mastercard $MA in 2006: 1) In '90s studied Buffett a lot, so familiar with American Express $AXP. $MA seemed like a better business to me in 2006 - less risk, less capital. 2) Studied and read Lynch in '90s -> S&L conversions got me thinking about demutualizations and positive effect on management incentives to grow profits. 3) Bot Chicago Mercantile Exchange $CME after demutualization and IPO in 2002. The Merc blossomed due to powerful shift towards electronic trading (GLOBEX) + improved profit motive + efficiency. 4) $MA Mastercard in 2006 seemed similar to $CME opportunity but maybe superior - better opportunity to capture shift to electronic payment from cash, better opportunity to grow operating margins after demutualization, better business model than $AXP. Seemed like a reasonable valuation for what COULD BE an excellent business. $MA certainly exceeded my initial expectations. Indeed, if I knew how powerful the shift to debit and credit cards, operating margin improvement, and share buybacks would actually play out I would have put much more into $MA. 5) I also bought $V in 2010 which is a multi-bagger but not nearly the returns of $MA in 2006. Markets learn and adapt so the returns diminish (notwitstanding bear market or massive temporary valuation dislocation for company or sector). History may rhyme instead of repeat but it's not a simple nursery school rhyme. One has to be a bit more sophisticated. 6) If I find a powerful secular trend and business model I do think opportunities may exist for a couple or even a few players. Home Depot and Lowes, Wal-Mart and Target, etc. [Don't own $HD or $LOW or $WMT or $TGT]. Always worth looking for other winners benefitting from same trend. For example, I bought and still own a number of alternative asset managers (decent size $APO, $ARES, $BX, tiny position in $CG) when they were K-1 generating publicly-traded MLPs. Great business models which were taking advantage of the shift from CUSIP to non-CUSIP investing (public to private). Also used to own $OAK Oaktree but Howard Marks proved to be a better talker and marketer than steward of shareholder capital. In fact $OAK was my first alt manager purchase. $OAK was slow to expand into ancillary verticals and new products, justifying their conservatism as prudence for their LPs and solid risk management. Then $OAK sold out to $BAM at exactly the wrong time for $OAK shareholders, putting their lofty talk and preaching in proper perspective. But by then I had sold large chunks of $OAK for $XPEL. If I had only bought $OAK years ago I would have gotten the secular trend right but chosen the wrong player. It's better to own a group in the beginning if a group is available and then narrow. 7) Finally, I'm not a never sell investor. I buy tiny positions of lots of stocks and sell the vast majority every year. What I try to avoid, however, is selling (trading away) the Michael Jordans. Admittedly, one takes on "superstar injury risk" in a concentrated portfolio but I think as long as you can AFFORD a superstar blowup the risk should be weighed against the reward. It is rare to have a Michael Jordan and one should be reluctant to trade him for The Unknown (or Less Well Known).