There are two standout reasons for this, a lower overall volume in the market (certainly a tiny fraction compared to Rolex) and the growth in the brand following, due in part to its unique motorsport connections. Some thought the December 2010 Bonhams auction of Arno Haslingers collection may see prices peak and fall back, akin to Omegamania some years before. However far from that being the case, values have continued their upward momentum. Of course prices that were paid at that event (a peak of £48000 for a PVD Monaco) were substantially higher than the "normal" market, but that would be expected for what was a very carefully choreographed and time consuming 12 months of PR beforehand. However since that auction, prices for the Heuer "Holy Grails" such as Chronomatic Monaco and "Siffert" variants and the PVD Monaco have pushed up to the region of £15000 - £20000 for the very best examples. I see no difference this year and expect the low interest rates, the growing awareness amongst watch collectors and investors and overall respect of the brand to continue to act as a benefit for values for some time to come.