Yes, they can be. A company can be created to compete with another company. Or a current company can start competing with another company.
One approach that a company can use to buy and acquire new competitor information is to swap information with the competitor. Your company may have information that the competitor company is interested in.
General Motors.
Palm
NVIDIA
Target is their biggest competitor.
general mills , nesle ralcorp
State Farm is one competitor..
the 3cs of marketing are Consumer Competitor Company
Forecasting your competitor's moves, making good business decisions, and identifying gaps in the market based on what your competitors are doing are some of the many advantages that a company can benefit from by the use of competitor intelligence.
Currently, the major competitor against the iMac is the PC.
For personal Computers it's Dell and Microsoft.
A competitor analysis is a person hired to figure out what the competitors are doing and how the company they work for will counter that competition. Essentially they investigate and suggest creative ideas to outdo the competition.