Because investing follows a power law, cutting your winners is the fastest way to destroy compounding.

The best knew this:

"The biggest error an investor can make is the sale of a Wal-Mart or a Microsoft in the early stages of the company's growth. Mathematically this error is far greater than the equivalent sum invested in a firm that goes bankrupt.” - Nick Sleep

“To realize 100 for one requires patience, extraordinary tenacity — the will to hold on.” - Thomas Phelps

"The hardest thing in the world is to do nothing when you have a winning position. The temptation to 'take something off the table' is the enemy of the massive multi-bagger." - Artur Walther

"To be a successful investor, you have to accept that the stock market is a giant distraction machine designed to make you interrupt your compounding. Mastery is the ability to ignore the noise and watch the grass grow." - Francois Rochon

"Selling winners and holding losers is like cutting the flowers and watering the weeds." - Peter Lynch

"The first rule of compounding: Never interrupt it unnecessarily.” - Charlie Munger