You'll read it on the Paul Fraser Collectibles website. You'll read it on investment-orientated literature across the internet.
"Past performance is no guarantee of the future".
Although rare autographs, for example, have grown in value by an average of 13.8% per annum since 2000, does that guarantee they will continue to rise in value?
Of course it doesn't.
At Paul Fraser Collectibles we can only offer our considered opinion, which is that demand (and consequently prices) for rare collectibles is going to rise over the coming years and decades.
That's down to a number of factors, including a greater appreciation among investors of the diversification benefits of the sector, the rising wealth in Asia, and the retirement of the wealthy baby boomer generation.
And new figures released this month suggest that we're on the right track.
Up 10.3% per annum
WealthInsight's 2020 Foresight Luxury Investment Report states that luxury investments will rise in value by 10.3% per annum to 2017.
The world's growing number of millionaires is expected to play a major part in those figures.
"Since 2007, an increasing number of millionaires have shown interest in alternative investments, such as art, classic cars, wine, jewellery, gems and watches, which in times of economic uncertainty can deliver higher returns than equities," states the report.
Ouliana Vlasova, WealthInsight's head of content, is also optimistic for future growth.
"Looking forward, millionaires' preference towards real assets is expected to drive demand for art assets and other collectables," she said.
Granted, it's just one report, but it is indicative of the positive buzz around the high-end collectibles sector.
A buzz, that if proved right, could make the prices I'm offering on these investment-grade collectibles seem very small indeed in a few years' time.
If you want to read the report in more detail, click here.
As ever, thanks for reading,