ABOUT

Art Market Research was founded by Robin Duthy in 1978 and is led today by his son, Sebastian Duthy. Independent, privately held, and based in London.

ORIGINS · 1978

A question with no easy answer — and a line of record for over two decades.

Art Market Research was founded by Robin Duthy in 1978 to address a single question: how do you measure the price of an asset when no two units are alike? Duthy — who wrote on the art market for a range of titles, among them the FT, Resident Abroad and Connoisseur — had been compiling auction prices on individual works since the late 1960s.

He formalised that work — in association with Professor Roy Strong at the London School of Economics — into a continuous index series: able to track artist and category-level prices over time, on a basis robust enough to carry tax-relevant valuations.

The Create-an-Index service — long known in the trade as ‘Duthy’s’ — has been published online continuously since 2002. A UK tax authority has used it as a reference in chattels valuation casework for over two decades and continues to rely on it today, including baseline valuations under Capital Gains Tax and post-transaction valuation checks.

Its indices have been relied on for benchmarking by the major international auction houses — including Sotheby’s and Christie’s — and by leading appraisers. The service is built for valuers, lenders, family offices and collectors valuing individual works, and informing consignment, acquisition and lending decisions.

IN PRINT · 1981

The bands became the method.

Page one of Robin Duthy's Investment File on the Impressionist market — the category index and the opening argument. The Connoisseur, September 1981. — Robin Duthy, The Investment File, The Connoisseur, September 1981. Reproduced with permission. Click either page to enlarge.

Page two — the price-movement and price/quality-band tables, with Renoir's five bands running from 154% at the top to 56% at the foot. The Connoisseur, September 1981. — Robin Duthy, The Investment File, The Connoisseur, September 1981. Reproduced with permission. Click either page to enlarge.

In September 1981, in his Investment File for The Connoisseur, Robin Duthy set out the problem the headline price concealed. Renoir looked up 180% across the decade — but that figure was an average of his top five works. Sort the wider field into five price bands and the picture splits: the top band up 154%, the lowest just 56%. And he trusted a reading at all only where works passed through the rooms in enough quantity, and regularly enough, to deduce the state of the market.

Every one of those judgements is alive in the valuation tool today — not as inheritance, but as method. The fair central figure he reached by separating the bands, the tool reaches by trimming them: the Central 80%, drawn the same way, but continuous where his was a single snapshot a decade wide — and now carried from any date to any other along a durable trend line, the AMR Trendline, the spine beneath every revaluation. The spread he had to tabulate by hand is now one plain sentence of the tool’s read — how wide the market runs. And the caution he placed on liquidity, trusting a figure only where works traded often enough to deduce the market, is now the gate— it weighs the durable move against the short-term noise and withholds the figure when the two can’t be told apart. He exposed the spread and hedged the reading because he had no way to hold either steady; the tool holds them, and surfaces each only when it bears on the number. The same rigour, gone quiet until it’s needed.

Renoir market by price/quality ranges, 1970 to 1980: the field split into five price bands, the top band up 154% and the lowest just 56%. From Robin Duthy's Investment File, The Connoisseur, September 1981.

TODAY · THE READ, ABSORBED

The live Renoir record today — the Central 80% market line (blue) with its durable AMR Trendline (burgundy) and sale volume beneath. One continuous read, where his was a decade-wide snapshot.