James Ede in a talk at Manchester University (October 25, 2014, 'Dealers: Trade, Traffic and the consequences of Demonisation')attacks the wild estimates that are often given for the value of the global antiquities trade. He says the IADAA has done some research on the volume of the open trade.
By analysing the publicly quoted figures of the auction houses and dealers worldwide and rounding the figures up quite dramatically we have arrived at a figure of €150-200 million per annum, ie around £150m. This does admittedly exclude one-off sales such as the Geurnol lioness and the Old Kingdom statue from Northampton [...], but these are rare. This figure of £150m is verifiable.It is not clear what this figure is intended to cover, just antiquities, or antiquities and 'tribal art'? Or something else? It is a shame that the figure is not broken down further into regions (the Americas, Africa, the Gulf) and themes (Egyptian, Pre-Columbian, Greece and Rome, Southest Asia),