Buying and Selling Stocks

There is no one best way to determine when to buy and sell stocks of  $Dow Jones Industrial Average(.DJI.US)$, $Nasdaq Composite Index(.IXIC.US)$, $S&P 500 Index(.SPX.US)$. The chosen strategy depends on our investment goals, investment philosophy and investment time horizon. The investment strategy I follow is one based on Warren Buffett's value investing model. The stock investing decisions will be made on the basis of risk evaluation. The three main risks are company, valuation and earnings risks. When the underlying company is great in terms of management and shows consistently high profitability, the company risk is low. When we are patient enough to buy a fundamentally well run company with sustainable competitive advantage whose stock price is at a steep discount to its intrinsic value, our valuation risk is low. When a company's earnings remain strong, the earnings risk is low. Once we are able to find a stock that that signals low risk based on these three conditions, it is time to buy. Even if the price were to dip in the short run, as long as our investment thesis is still valid, our focus should be on long term gains as fundamentally strong stocks tend to always go higher in the long run. Whenever a negative change happens to any of the three conditions,  it is time to sell. When it comes to selling, we may decide to sell stocks once the price gets close to their fair value which implies that there is limited upside left and we could then reinvest the proceeds into stocks with higher potential upside for better returns.
$Apple(AAPL.US)$
$Microsoft(MSFT.US)$
$Alphabet-A(GOOGL.US)$
$Amazon(AMZN.US)$
$Facebook(FB.US)$
$Tesla(TSLA.US)$
$NVIDIA(NVDA.US)$
$Visa(V.US)$