There is no SI3 clarity grade in the clarity grading scale of the Gemological Institute of America (GIA). The GIA lab does not issue lab reports with an SI3 clarity grade. But the Rapaport Diamond Report, which is the most widely used price sheet in the industry publishes prices for an SI3 clarity grade and the European Gemological Laboratory (EGL USA) issues lab reports with an SI3 grade.
Rapaport and EGL USA did this as a way of recognizing the distinctions New York dealers were making in their trading between eye clean I1 clarity diamonds and I1 diamonds that were not eye clean. Better, or eye clean I1 stones were simply worth more money than I1 diamonds that were not eye clean. Thus, a new clarity was born from the distinctions that traders made among I1 stones. First Rapaport and then EGL USA recognized those distinctions. GIA never has.
The problem for calculating loan value is that we always want to loan as much as we can and so we are tempted to use the SI3 clarity grade. But if we have to sell the diamond, the dealers will want a GIA lab report (EGL is in disrepute) and most SI3 stones will get an I1 grade from GIA. The 1.50 carat round diamond we have been using as an example is worth $900 less as an I1 than an SI3 and we would be unable to recover what we have loaned out.