A stock index at a given time is a ratio of prices of the constituent elements in relation to the prices in the reference instant when the index began.

It indicates the value of a basket elements, not whether evolution of that value is good or bad.

To evaluate the performance of the index in the last 52 weeks, we calculate the ratio between what has risen from the minimum and the difference between the maximum and the minimum of 52 weeks.

This indicator will be corrected, penalizing a part based on a similar ratio refered to the current session (or last); and partly based on the percentage that represents the range of 52 weeks in relation to the current price, in the event that does not exceed a certain predetermined threshold.