rerating, page-7

Just to add a bit more to marketguru's outline...

A company's "rating" at any time will be in line with the known facts about the company, and the market sentiment in comparison with it's peer companies and sectors at that time. A company's "rating" is different from its share price / market capital value - the share price / market capital will vary every day (one day it is worth $1m, next day $900k, the day after $1.1m). Such movements are not re-ratings just day to day price gyrations.
A re-rating would see a substantial increase or decrease in value based on new events / activities within the company (or even market segment). Such activities could be a miner going into production, an oiler making a significant discovery, uranium mining being opened up etc....essentially something that makes a fundamental shift in the company's prospects. I don't regard a little oiler that goes from 10c to 20c on speculation of a hole to be drilled as a re-rating...I do regard it as a re-rating when the same oiler goes from 20c to 3c when that drilled hole is found to be dry (you don't have to look FAR to find one of those lol).

So essentially a re-rating, positive or negative, will generally occur due to a material event within the company or sector which changes the sentiment.

I hope that makes sense