138In the present case, it must be pointed out, first, that the applicants have not elaborated on their argument on HHI value brackets, even though they knew the exact market shares used in the contested decision as soon as the Commissions defence was lodged. However, the HHI calculated on the basis of those figures is shown to increase from around [confidential] pre-merger to about [confidential] post-merger, which represents a delta of approximately [confidential]. Those values indicate that the effects of the merger on the market exceed the HHI thresholds below which the merger does not, in principle, raise any competition concerns. However, the second sentence of paragraph 21 of the Guidelines states that exceeding those thresholds does not give rise to a presumption of the existence of competition concerns. It must be observed, however, that the greater the margin by which those thresholds are exceeded, the more the HHI values will be indicative of competition concerns.