Stack Infrastructure has announced its plans to build a second data center in Portland, Oregon. Bringing its U.S. portfolio to nine data centers.

The Portland facility is the third planned data center announced by Stack in six months, after raising $850 million from selling shares in its existing sites to equity investors.

“Portland is a key market for our clients and, consequently, for Stack,” said Matt VanderZanden, chief strategy officer, Stack. “Its unique attributes are proximity to key user bases, excellent network and electrical infrastructure, and sources of renewable energy.”

Stack was recently created by Investment fund IPI Partners, starting with the six data centers it had acquired from other companies. IPI then raised the expansion funds which amounts to $850 million in January for Stack Infrastructure.

“This is only the beginning of the presence Stack intends to build,” said Brian Cox, chief executive officer, Stack. “We view this as a high-priority market for ongoing investment.”

According to Stack, Hillsboro, which is outside of Portland, was connected to international markets by a subsea cable. And Cox said that the new Portland data center would be a significant, long-term expansion in Hillsboro. This is where its first data center was built in 2012. “It is where we’ve built some of our most important and enduring client relationships,” adds Cox.

In January, the company said it would build another Texas data center at a computer campus operated by Hillwood, a real estate firm that has a strategic alliance with IPI. Also in June, Stack disclosed its plans to build a second data center in Chicago. It would be a multi-story facility with 20MW power capacity, adding to the existing site’s 13MW.

The ratings agency Standard & Poor’s (S&P) reported that Stack’s first six data centers were worth about $500 million, and made about $78 million a year in rent. However, Stack had sold about 60 percent of their value as shares.