In this article, Serge Milman explains the high costs of adopting a tail spend category. Unmanaged Spend ≠ Spend Category. Tail Spend is not a spend category, and thus cannot be sourced effectively. Tail Spend – or more accurately, Un-managed Spend – is an aggregation of spend and vendors that typically represent 40%-60% of total spend. Attempting to source Tail Spend as a category makes about as much sense as including Professional Services and Technology Hardware into a single RFP….