For third-party logistics, 2015 was a year dominated by mergers and acquisitions, ample carrier capacity, and sagging fuel prices.

That’s how the 3PL year was characterized in a recent report from Armstrong & Associates.

3PL net revenues grew 4.5 percent in 2015 to $71.9 billion. Overall gross revenues had a muted 2.2 percent increase, primarily due to reduced fuel prices in 2015 versus 2014 and the resulting reduction in fuel surcharge revenue for non-asset domestic and international transportation managers. The total U.S. 3PL Market expanded to $161.2 billion.

Big M&A deals changed third-party logistics from mid-2014 through 2015. XPO Logistics helped make 2015 the largest 3PL M&A year (with purchases including Con-way and Norbert Dentressangle) for deals over $100 million at 11, since Armstrong & Associates began tracking activity in 1999. The resulting integration of operations have increased concentration on efficiency and profitability.

For 2015, the domestic transportation management (DTM) 3PL—also known as freight brokerage—segment lead the way with net revenue growth of 12.4 percent, Armstrong reported. International transportation management (ITM) rebounded with 4.8 percent net revenue growth. Dedicated contract carriage (DCC) net revenue saw muted growth of 4.0 percent due to ample carrier capacity in the market. While many 3PL warehouses were full in 2014 and 2015, pricing pressure has dominated the competitive landscape. Value-added warehousing and distribution (VAWD) had a meager 2.2-percent increase in net revenue for the year.

The big story in warehousing, according to Armstrong, was Amazon’s sequential growth in its fulfillment center operations. If all of Amazon’s warehouses, accounting for 100.6 million square feet of space were counted as 3PL VAWD space, it would be the third largest global VAWD 3PL behind DHL Supply Chain & Global Forwarding with 248 million square feet and XPO Logistics with 151 million square feet. “Amazon is also growing its internal freight forwarding and domestic transportation management skills,” said the Armstrong report, “so we are awaiting the day when it truly goes to market as an integrated 3PL. It has already described itself as a transportation service provider in a recent 10-K filing.”