Table - Net US Search Ad Revenues By Major Ad Networks As % Of Spend

Newly available data suggests, while Microsoft has decreased its TAC over time, their initial costs of acquiring search traffic were far higher than eMarketer previously estimated, triggering a downward revision to estimates of Microsoft ad revenues in recent years. eMarketer now estimates that Microsoft will account for 4.6% of total US search ad revenues in 2013, revised down from the 9.3% share we predicted it would take in March 2013, with the difference likely paid to the company’s ad partners. Read the rest at eMarketer.