Price is the best metric, but a metric is a standard for measurement, not an accurate measurement. Apple went from $392 a share on April 4th to as low as $353 just before yesterday's close. Are you telling me that apple lost $36 billion in value over a period of 5 days, or that it gained $5 billion in value today?

The market is a voting machine in the short term and a weighing machine in the long run. Saying that Apple is now the world's most valuable company is a stupid statement because it's based entirely on today's market cap.

Most people understand that Stock Price relates to current assets AND expected future returns. What most people miss, is that the value of future returns vary's based on the price of other investments. Conciser if 3 year US treasury bonds had a yield of 17% then the value of most stocks would tank as their future earnings become less valuable today.

So, when the market crashed the value of Apple stock drops even if their future earnings are unaffected.