The most expensive musical instrument ever offered to the market has been unveiled in New York with an asking price of $45m. 

The 'Macdonald' viola by Antonio Stradivari was owned by Peter Schidlof, the Austrian-British viola player and co-founder of the Amadeus quartet. Although he didn’t always play the Macdonald in the quartet, its golden sound was beautifully evident when he did: the instrument has a distinctive alto quality that isn’t as dark as that of many violas, but which manages to maintain its extraordinary power despite its sweet and deceptively light tone. All this was demonstrated by David Aaron Carpenter, who played the instrument at Sotheby's in New York - you can watch the film here. 

Schidlof’s family, having lodged it with a well-known dealer after his death in 1987, is offering the Macdonald for sale through the New York offices of Sotheby’s, in conjunction with the London specialist auctioneers Ingles and Hayday. Tim Ingles, director of Ingles and Hayday and previously the head of Sotheby’s musical instruments department in London, said:

'This has been a long-awaited event in the violin world. The instrument has been locked away for the last 27 years and over that time it has acquired almost mythical status. Everyone knows about it, but hardly anyone has seen it, so that enhances the excitement as it comes to the market.

'We’re enormously privileged to be handling the sale.'

The viola was made in 1719, near the end of Stradivari’s 'Golden' period – the period during which he made the instruments commonly held to be his greatest work. Stradivari made around 660 instruments, of which the vast majority are violins.  There are around 60 existing cellos, but only ten complete violas, making them by far the rarest examples of Stradivari’s work. 

The Macdonald is one of only two Stradivari violas in private hands. The other, the 'Tuscan' contralto (one of two known as such), is in private ownership but held in the Library of Congress and is unlikely ever to be sold. Both instruments have lain dormant for a number of years and now that the Macdonald has appeared in the public domain – potentially for only a short time – there is the exciting possibility it will pass into the ownership of a collector or foundation that will allow it to be played. Were that to happen, the famed and unique sound of the Macdonald could only improve, but the question of who would buy such an instrument is difficult to answer. 

When certain Stradivari violins are offered on the open market it is often presented as a 'once-in-a-lifetime opportunity' when, in fact, those instruments will more likely than not appear for sale every couple of decades. The appearance of a Stradivari viola on the market, though, is genuinely unlikely to happen more than once every generation. So, the question is: is $45m a realistic amount to be asking for a single instrument, regardless of its historical or rarity value?   

The Lady Blunt Stradivari violin, currently the world record for a violin at auction, made upwards of $15m when it was offered for sale by on-line auction house Tarisio in 2011. There have been enough private sales of Stradivari and del Gesù violins that have made slightly in excess of that figure in the intervening years to suggest that the highest deals on the greatest violins are being made around the $20m mark. But who are the buyers in a position to take that opportunity? To own a full Stradivari quartet may without a doubt be the pinnacle of instrument collecting, and this will be the last opportunity for anyone aspiring to that to complete a set, but there are very few collectors, or even institutions, with the funds to buy an instrument at that level. There are a fewer than a handful of buyers of musical instruments – either foundations or private individuals – with that kind of proven track record.

The sale will be conducted by sealed bids so, although strictly speaking an auction, it is entirely possible that the actual figure the instrument realises may never be made public. Were it to sell for its asking price or, even, a reduced amount of around $30m (which might be suggestible as a more realistic valuation), its status as a playing instrument may nevertheless be compromised by its value. Simply moving it around the world for concerts would create vast expense in terms of insurance and travel to the point where it may be considered to be more of a poisoned chalice than an indication of the true value of the instrument. Certainly, the instrument’s place in the wider context of the musical instruments market would be impossible to estimate as it sits so far outside its orbit. 

One thing is for sure, though – whatever this instrument sells for, it will be a record that will likely remain unmatched for generations to come. Whereas most record-breaking sales of musical instruments are like shooting stars, whose tails pull future prices up with them, the Macdonald viola is like an asteroid – shooting through the instrument firmament, with absolutely nothing in its wake.