It's simple math - Go to http://finance.yahoo.com. Enter the ticker symbols. Outstanding shares multiplied by the share price determines the market capitalization. Compare the market cap values. Exxon is #1, and Apple is #2, and the trend is working in Apple's favor. But with the volatility in energy stock prices, Exxon and Apple may be in a see-saw battle for the #1 position for a while.
“It’s simple math”
Then it should be easy for you to post.