Enid Tsui is a tough customer. Her assessment of new book by a former auction house executive—”It doesn’t reveal any real secrets”—makes that clear. Nonetheless, she finds some virtue in the tome.

Many will remember Brett Gorvy telling the Wall Street Journal that he kept a list of 141 potential buyers above the $50m mark. Gorvy said that in 2014. And he added that the list was fluid with names coming on and going off.

Now Tsui quotes one of his former colleagues going further down the buying pyramid:

Apparently, in 2015, auction houses believed that only 140 people worldwide had the means and desire to spend US$50 million or more on a work of art. For objects worth about US$20 million, there were 300 poten­tial bidders, and at US$5 million, the number was closer to 1,000.

The more interesting question these days is how many buyers are there for works $500k to $1m?

Caught the collecting bug at Art Basel? Former Christie’s exec can guide you through the labyrinth (South China Morning Post)