There's something illogical in the French text - it is saying that the 'non-loss' of transactions should be kept low!

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Note added at 1 hr (2006-03-24 14:41:06 GMT)
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From a grammatical standpoint, 'celle-ci' refers to the preceding noun, which in the sentence in question is the complete noun phrase 'non perte de transaction'. We must read this as an indivisible noun phrase because it is being used as such in the earlier part of the sentence where it is set against 'disponibilité' and 'performances'.

From a logical standpoint, 'celle'-ci' needs to refer to 'lost transactions', since it is these which must be kept within bounds, but there has been no explicit mention of 'lost transactions' earlier in the sentence.

If we substitute 'celle-ci' with the nouns it refers to we get:

... qui seront toujours privilégiées à la non perte de transaction, dans la mesure où la non perte de transaction reste limitée.

and

... qui seront toujours privilégiées à la non perte de transaction, dans la mesure où les transactions perdues restent limitées.

This demonstrates that 'celle-ci', singular, ought logically, to read 'celles-ci', plural, although this would be grammatically incorrect.

At the end of the day, the French would be clearer - and correct from both the grammatical and logical standpoint - if it read:

... qui seront toujours privilégiées à la non perte de transaction, dans la mesure où les pertes restent limitées.