Total estimated sales at art fairs reached $13.3 billion in 2016, an increase of 5% from the prior year and up 57% since 2010. The share of dealers’ sales at international fairs rose 7% in 2016, while sales at local fairs fell 6%. But art fair costs are rising too, a burden that falls on all dealers, not just the ones whose sales are up. Fairs were the largest area of dealer spending in 2016, representing 22% of their total costs, or $4 billion, up 6% from 2015. That was followed by marketing, at 20%. The fastest-growing area of expenditures was on IT, which soared 85% from 2015 to $2.3 billion.