Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Are the stocks of competitor companies negatively correlated?
In theory, say we had two soft drink companies, and no other existed. On Jan 1, they report they each had 50% market share for the past year. Over the next year, one company's gain is the other's loss. But over the year, for whatever reason, the market has grown 10% (all the stories of bad water helped this), and while the market share ends at 49/51, the 49 guy has improved his margins, and that stock rises by more than the other.  In general, companies in the same industry will be positively correlated, and strongly so.  I offer my "spreadsheets are your friend" advice. I took data over the last 10 years for Coke and Pepsi. Easy to pull from various sites, I tend to use Yahoo. In Excel the function CORREL with let you compare two columns of numbers for correlation. I got a .85 result, pretty high. To show how a different industry would have a lower correlation, I picked Intel. Strangely, enough, Intel and Pepsi had a .94 correlation. A coincidence, I suppose, but my point is that you can easily get data and perform your own analysis to better understand what's going on.