The Seattle and Tacoma port commissions plan to unify the management of the two ports’ marine cargo terminals and related functions in order to strengthen the Puget Sound gateway and attract more marine cargo for the region.

The Seaport Alliance will manage marine cargo terminal investments and operations, planning and marketing, while the individual port commissions will retain their existing governance structures and ownership of assets.

This agreement between the state’s two largest container ports is a strategic response to the competitive pressures that are reshaping the global shipping industry, according to both port commissions.

“The ports of Seattle and Tacoma face fierce competition from ports throughout North America, as shipping lines form alliances, share space on ever-larger vessels and call at consolidated terminals at fewer ports,” said Port of Tacoma Commission President Clare Petrich. “Working together, we can better focus on financially sustainable business models that support customer success and ensure our ability to reinvest in terminal assets and infrastructure.”

Combined, the ports of Seattle and Tacoma are the third-largest container gateway in North America. A recent analysis estimates that the two ports’ marine cargo operations supported more than 48,000 jobs, which generated nearly $4.3 billion in economic activity in 2013.

“Where we were once rivals, we now intend to be partners,” said Stephanie Bowman, co-president of the Port of Seattle Commission. “Instead of competing against one another, we are combining our strengths to create the strongest maritime gateway in North America. The Seaport Alliance is the result of our shared commitment to maintaining the economic health of our region through a thriving maritime industry.”

The Seaport Alliance is subject to Federal Maritime Commission review and approval. Following a due diligence period by both parties, the two port commissions intend to submit a more detailed agreement for the Seaport Alliance to the FMC by the end of March 2015.

The two commissions expect to formally adopt and move to submit the agreement to the FMC at a joint public meeting Oct. 14.