The problem with your hypothesis that Warren Buffet is lying about "not selling" your stock profits him is that his stock purchase/sell record is public knowledge and it "refutes" your hypothesis. While Warren Buffet will make changes to his portfolio, he always has reasons why he does so. Many stocks he "keeps forever" such as KO. If he does feel the wind has changed, he will add to his position or sell, as he sees fit.
What the "you dont make any money until you sell" people fail to realize is that is actually not true.
One such reason is that many people have margin accounts, or else they can borrow money on securities such as one could with your home.
If your home increased in value, from say, 10,000 dollars to 300,000 dollars you can borrow on your equity and invest that money in something else.
Ditto for a stock. If your stock portfolio increases significantly, you can borrow money using it as collateral and purchase other securities if you so desire. This way, you dont have to sell a great stock to take profits and miss out on future gains by investing in a worse stock.
News 
Market Data 
Discover 
AI
