Decanter magazine publishes an auction index for Bordeaux. Currently the index, set in December 1996, is at 117.6 (ie up only 17%) that’s below the inflation rate over the same 9 year period. Very odd, unbelievable actually, unfortunately they do not explain fully how they calculate their index.
Langton’s the Australian auction house maintains an index set at 1000 in 1991 it is now slightly over 2000. If it had only risen with inflation it should be at 1400 now. Oddly though the index reached 2500 in 1999 after which it dropped and has been flat for 5 years now.
Wine auction indices are somewhat odd in that a single vintage typically rises in price then stalls and even can decline, eventually vintages have to be removed and new ones added. Wine auction indices seem really only useful for comparing changes over a few years.