The investment and collecting market for rare Scotch whisky is booming with auction sales of bottles of single malt up 35% in the first half of 2015.

Whisky investment analyst and brokerage Rare Whisky 101 said its review of auction house figures showed that 20,638 bottles were sold in the first half of the year with a combined value of £4.6 million, a 33.8% rise on the first six months of 2014.

Rare Whisky 101 co-founder Andy Simpson said a move by leading brands such as Macallan away from age statements on their current retail supplies was making older and rarer whiskies more attractive to enthusiasts.

“Demand for rare whisky and the supply of bottles at auction are both accelerating at an extraordinary rate and this is driving up values,” he said.

“Demand for desirable single malt Scotch brands and previously discontinued bottles remains exceptionally strong.

“The dead hand of marketing is gaining an ever tighter grip on the single malt category, where retail releases are becoming non-age stated and the number of bottles ever more prolific.

“The dearth of truly collectable releases over recent years has only fuelled demand for older and discontinued past releases where quality and rarity are powerful motivations for purchase.

“For many in the broader Scotch industry, export and sales figures appear challenging. However, the secondary market shows little of this stress.

“We see this as a clear future trend, with the value of scarcity increasing demand from connoisseurs, collectors and investors.”

The top 100 performing bottles of investment-grade Scotch increased in value by 8.9% in the first half of the year and values have increased overall by over 500% since 2008.

The dormant Brora distillery and Whyte & Mackay-owned Dalmore are the top-ranked distilleries in the investment market, followed by Port Ellen, Mortlach and Bowmore.

Rare Whisky 101 also reported strong interest in Japanese whisky with values of Karuizawa up 66% on a year ago.

Its report came as the Japanese distiller broke the world auction record for a single bottle of whisky from the country.

Bonhams in Hong Kong sold a bottle of 1960 Karuizawa The Cockerel for HK$918,750 (£77,297).