The group backing a bid to build a baseball stadium along the Portland waterfront and lure a Major League Baseball franchise to this city has released the names of 18 investors backing the early stages of the effort.

The names of investors in the Portland Diamond Project have remained a closely guarded secret until now. The MLB backers announced the involvement of pop singer Ciara and Seattle Seahawks quarterback Russell Wilson earlier this year, and WW revealed the financial support of electrical supplies magnate Harvey Platt this month.

Tonight, the Portland Diamond Project released to WW the names of the first 18 "Charter" investors in the stadium effort. Few of the other investors are household names, although they include the founder of hip sportswear boutique Portland Gear, a former Toronto Blue Jays player, and a Nike executive.

The Oregonian independently reported tonight that Portland Mayor Ted Wheeler's office has reviewed commitments from out-of-state equity investors totaling $1.3 billion. That's all  significant portion of the estimated $2.5 billion that will be required to build a stadium along the Willamette River and pay an expansion fee to Major League Baseball.

Yet the group faces a recent financial obstacle: WW reported last week that Oregon lawmakers, including Sen. Ginny Burdick (D-Portland), have drafted legislation to strip away a potential $150 million in tax breaks that would fund the project.

The Portland Diamond Project said the early investors have funded "the initiative's overall operations, including ballpark and development design, legal services, government relations, communications, community engagement and branding."

Baseball Project spokesman John McIsaac says that future investors will supply the funding for a ballpark.

Here's the list of investors released tonight by the Portland Diamond Project:

• Seattle Seahawks quarterback Russell Wilson
• Recording artist and entrepreneur Ciara
• Former MLB player Darwin Barney, father David P. Barney and brother David M. Barney
• Retired business owner and philanthropist Samantha Richardson
• Former CEO of Platt Electric Harvey Platt and wife Sandy
• Opus Agency co-founder and restauranteur Grant Hammersley
• Portland Gear founder and CEO Marcus Harvey
• Kamp Grizzly founder Dan Portrait and wife Sheena
• Avamere Group founder and CEO Rick Dillon
• DWFritz Automation CEO Mike Fritz
• Nike Inc. Vice President of Global Footwear Product Creation Mark Allen and wife Peg
• Jevo founder and entrepreneur Tyler Williams
• Real estate broker Kelsey Williams