"Do you have a view on the asset class "oldtimer cars"? The price increases are staggering as documented by auction results.
"If you don't follow this asset class. Would you be able to guide to prefessionals in this area?"
David Fuller's view I like the diverse Collectables field and have often written about it over the years. The most important point is that you have to really love the collectables that you are considering. That way you will learn a fair amount about them and enjoy them once purchased. I call that the 'yield to the spirit', because they will never pay cash dividends.
It is also a fashion game and that influence is often hard to predict. However, a low interest rate environment and the prospect of recovering economies is a favourable environment, as we are currently seeing across many collectable categories.
I would generally avoid the 'professionals' in the collectables field because they will see you coming. The exceptions would be people who you really know and more importantly, can trust. Even then, the retail mark-up is huge. In jewellry, for instance, it can easily be two to three times what the jeweller paid, especially when buying from a distressed seller.
Auctions are better, if you know what you are doing and can find what you want, but the buyers premium is high at around 25% for moderately priced items. Once purchased, you have insurance and storage costs so it is an expensive hobby, not least for purchasers of 'oldtimer cars'.
Collectables can be a reasonable long-term investment but a quick return for anyone other than the retailer is the exception rather than the rule. If you bought a collectable from one retailer and sold the same item to another retailer a few days later, it could easily cost you 50% of your money.