Why no Benchmark SI-IRR in Sample 4 on Page 52 of GIPS Standard?

Yes, the notes of sample 4 states that the SI-IRR benchmark is not available. But 6.A.26 shows SI-IRR benchmark is a must.

i don’t have the notes in front of me, so im going off of memory, but i belive the SI-IRR is required for the portfolio, but if you don’t have it for the benchmark you have simply have to explain why…

If the the benchmark is unvailable, the firm must explain why, as specified in the general provision.

It’s a little different in this sample, since the income/capital/total returns of the benchmark are all provided. You should be right, it tells that the benchmark SI-IRR is not available for the 2006 vintage year. Perhaps the relevant data for the calculation are not available from the benchmark provider.