Forrester estimates that B2B eCommerce will top $1.1 trillion and account for 12.1% of all B2B sales in the US by 2020. At the end of 2015, Forrester expects eCommerce to reach $780 billion and represent 9.3% of total B2B sales in the US. We're forecasting a compound annual growth rate (CAGR) of 7.7% in B2B eCommerce over the next five years — driven largely by channel-shifting B2B buyers and the desire by B2B companies to reduce their costs to serve clients. This report defines the potential of the US B2B eCommerce space and what B2B eBusiness and channel strategy professionals must do to take advantage of the opportunity.