HHI and 4-Firm Concentration

Hey guys, I am confused with the break down for both the ratios. In the book it says Highly competitive and Competitive etc… etc. I want to make sure that my answer is going under the right categories i.e Oligo… MC… Mono…PC

http://www.analystforum.com/phorums/read.php?11,752567,752630#msg-752630 Post Back if you still cant fig it out.

Just remember that if the numbers are high, competition is low. If 4 firms have 95% of the marketshare, it isn’t very competitive and is either a monopoly or oligopoly. If 4 firms have 20% of the marketshare, it is highly competitive because no one competitor (or small group of competitors) makes up the majority of the market. This market would be a perfect competition or more likely monopolistic competition.