Georgina Adam traces the history of dealing during the Venice Biennale in the Financial Times and shows its hardly new:

[T]he art market laps into Venice long before anyone has even got to Basel. For a start all the art dealers are there, laying on smart parties in yachts or in palazzos for their select clients. Deals are wrapped up between the Giardini park and the Molo pier, poolside at the Cipriani or over prosecco in the Danieli. At the 2007 biennale, for instance, Christie’s owner François Pinault snaffled Polke’s much-admired suite of paintings, “Axial Age” (2005-2007), which were exhibited in the centre of the Italian pavilion, from Polke’s dealer Michael Werner gallery within days of the opening. The paintings go on show this month in Pinault’s new Punta della Dogana museum, which opens today.

Again in 2007, London’s White Cube gallery was openly selling works by the much-contested British selection, Tracey Emin,at prices between £3,000 and £100,000; more than 75 per cent of the works at the British pavilion were sold, the gallery said at the time, before the Biennale officially opened. […]

In fact, selling art used to be an accepted part of the Biennale. Between 1942 and 1968, the Italian dealer Ettore Gian Ferrari had the official job of placing works for any willing artist, earning 15 per cent for the Biennale and 2 per cent for himself. This was stopped, ostensibly so that the Biennale was not commercially tainted, although Ferrari’s daughter Claudia says the real reason was that the artists’ regular dealers began to object to the practice. […]

The online database ArtPrice tends to confirm the “Biennale boost”. Its indices show that Tracey Emin’s prices rose by 34 per cent in 2007 and Gilbert & George’s by 85 per cent in 2005, in each case the year they were selected for Venice, while Robert Gober, the 2001 US selection, saw his auction prices rise by 184 per cent in 2000, drop by 7 per cent in 2001 and then rise by 30 per cent in 2002.

Trading Places (Financial Times)