There's a lot of it about in Britain at the moment, despite several recent successful prosecutions. Public companies supply a list of their shareholders to some outfit with a reassuring-sounding name such as Beresford Boosey or Solid Liquid Investments. Said outfit mails the shareholders personally with a letter, typically offering them a 'free market report on any plc of your choice' (big deal).
The real sting however is that the outfit 'would like to take a few minutes of your time to introduce you to the highly profitable vintage fine wine market'. Much is made of the fact that profits made on wine are tax free. (This fact tends to be trumpeted only sotto voce by the core fine wine traders for fear the situation will change).
I have one such letter here (sent to my brother, one of the people least likely to invest in wine that I can think of) which uses a couple of highly selective examples to supposedly illustrate the fabulous profits to be made on wine. One of them is 'Chateaux (sic) Le Pin 1982' which could have been bought for £200 in 1983 and – guess what – is now worth £18,700. The clear suggestion is that the fine wine market is full of such plums to be picked out with your thumb, so long as you're guided by this dubious outfit.
Except of course, the outfit is very far from the hub of the fine wine market. So far that they don't even know how to spell Château. And all you can depend upon is that a) they are hoping you know nothing about wine either and b) that the prices they quote will be quite breathtakingly high compared to the market norm.
For more specifics, consult Jim Budd's site www.InvestDrinks.org and see my previous piece Beware Dodgy Hawkers of Fine Wine and my list of trustworthy Fine Wine Traders.