Article 7
Calculation of the Spearman correlation coefficient
1. Institutions shall calculate the Spearman correlation coefficient referred to in Article 6(1) of this Regulation by performing the following steps in the following order:
(a) |
they shall determine the time series of observations of the hypothetical and theoretical changes in the trading desk portfolio’s value for the most recent 250 business days; |
(b) |
from the time series of the hypothetical and theoretical changes referred to in point (a), institutions shall produce the corresponding time series of ranks in accordance with paragraph 2, treating the time series of the hypothetical and theoretical changes as the originating time series; |
(c) |
they shall calculate the Spearman correlation coefficient in accordance with the following formula:
Where:
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2. Institutions shall produce the time series of ranks referred to in paragraph 1, point (b), from an originating time series by performing the following steps in the following order:
(a) |
for each observation within the originating time series, institutions shall count the number of observations with a lower value than that observation within that time series; |
(b) |
institutions shall label each observation with the number resulting from the calculation set out in point (a) increased by one; |
(c) |
where, as a result of the labelling in accordance with point (b), two or more observations are labelled with the same number, institutions shall in addition increase the numbers of those labels with the following fraction:
where N equals the quantity of the labels with the same number; |
(d) |
institutions shall consider as time series of ranks, the time series of the labels obtained in accordance with points (b) and (c). |
3. Institutions shall calculate the standard deviation of the time series of ranks RHPL in accordance with the formula laid down in point (a), the standard deviation of the time series of ranks RRTPL in accordance with the formula laid down in point (b), and the covariance between those time series in accordance with the formula laid down in point (c) as follows:
(a) |
; |
(b) |
; |
(c) |
; Where:
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