This is what it would look like in normal English as used by someone working in or familiar with the financial industry "as she is" in the US. What it means is that the data sample used to calculate average performance metrics, such as earnings, capitalization, loan portfolio performance, etc. should cover at least the preceding seven years.

The original Russian sentence is an absolute abomination (a string of 6 genitives, the record being seven, no?) and it results in an even bigger one when translated into English anywhere close to the original. You need to rephrase.


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Note added at 1 day1 hr (2014-08-28 13:27:17 GMT)
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Sure, you can say "... that to ensure reliability, historical data used... blah blah". There isn't really anything about financial performance metrics that would make them particularly "reliable" or "robust" in the engineering sense. They are ratios - such as price to earnings, price to book, percentage of bad loans in the bank's portfolio (actually, probably a whole bunch of those in this case, I am not much of a banking expert), etc. There is no reliability issue involved - not in the sense of, say, being able to reliably measure a vehicle's speed, or the engine's RPMs, or a person's weight without being off by ten pounds. There is no such risk with financial ratios. They are just formulas. If a regulator or industry group, such as Basel, believes that 7 years of performance data is sufficient for their purposes (which is mostly for disclosure) to calculate the ratio, then that's all you have to do, plug the data in and make sure the calculations are accurate. That's it. Of course, for the most part both you and your regulator still come out wrong - because, as they say in mutual fund prospectuses, past performance does not guarantee future results - but that's already a totally different story. Cheers.