For generations, one of the largest and most lucrative asset classes in the world was the exclusive preserve of a small and very privileged group of wealthy individuals.

Ranging from gleaming office towers to hotels, malls and warehouses, the asset value of the U.S. commercial real estate sector is pegged at a massive $6 trillion, behind only stocks and bonds.

Yet access to investment opportunities in this real estate market long required deep pockets, as developers built connections within country-club circles and corporate boards to help finance their projects.

Access matters, especially when it comes to the commercial real estate market. It's traditionally racked up returns on par and greater than stocks, and now offers added diversification to stocks.

But membership in that once exclusive investment club is changing, and changing fast, with the emergence of online platforms that have dramatically opened up the world of commercial real estate investing, putting it within the reach of millions of people who had previously been shut out of an insider's game.

Leading the transformation is CrowdStreet, a Portland, Ore.-based online marketplace through which individual investors can reap the rewards of investing in everything from multifamily apartment buildings to hotels and office buildings.

Since launching in 2014, CrowdStreet has placed more than $525 million from thousands of investors in new and existing projects across the country.

"It's the first time in the history of our country that the typical investor doesn't have to go to the publicly traded exchanges in order to invest," notes Tore Steen, CrowdStreet's chief executive officer and co-founder. "We are riding that opportunity."

The investment opportunities CrowdStreet is opening up in commercial real estate offer a crucial source of diversification and added returns for investors who are worried that their stock portfolios might take a beating on Wall Street.

Investors in commercial real estate are reaping handsome returns, with office and multifamily rents alike hitting record heights across the United States.

For its part, CrowdStreet got its start in the aftermath of the mortgage crisis and the Great Recession that followed. Steen, along with friend and commercial real estate executive Darren Powderly, built an investment platform to democratize access to the lucrative and less volatile asset class. Their solution was an online marketplace that enabled real estate developers to quickly raise capital from investors for as little as a $25,000 investment.

"When Darren first approached me with the concept, my initial question was: 'Why hasn't anyone thought of this before?'" Steen recalled.

Powderly explained that a shift in federal laws and regulations opened the door to this new way of raising money for projects.

A fortuitous act of federal legislation, the 2012 JOBS Act (Jumpstart Our Business Startups Act) laid the groundwork for both crowdfunding ventures and use of these new platforms to raise money for commercial real estate ventures.

The legislation -- and subsequent regulations rolled out by the U.S. Securities and Exchange Commission -- were designed to provide a boost to small businesses by enabling them to tap a much wider group of investors than ever before.

The law eased restrictions that had prevented developers and private real estate from reaching out online to accredited investors, those earning $200,000 or more annually or holding a minimum $1 million in assets not including their primary homes.

Prior to the legislation changes, developers and real estate firms often relied on small, locally based networks of wealthy ultra-high net worth individuals who gained ground-floor access to projects with the potential to spin off double-digit returns.

CrowdStreet's platform today enables developers and real estate firms to reach an exponentially larger audience of potential investors than ever before.

Five years in, CrowdStreet's platform has connected over 40,000 accredited investors with development projects from over 300 sponsors in 42 different states, ranging in size from $10 million to over $100 million.

CrowdStreet has deliberately focused on accredited investors, which differentiates its platform from growing field of real estate crowdfunding platforms. These investors can invest directly with the real estate sponsor, which has attracted top-quality, institutional deals to the site.

"Insert technology into this and you have the ability to take your offering across the country to accredited investors and bring in more investment dollars and widen your pool of capital," Steen said.

Added Steen: "We are taking the heavy lifting off of the [developers]. They would never know how to go out and find tens of thousands of accredited investors."

And CrowdStreet's platform, in turn, has helped democratize commercial real estate investing, opening up a field once restricted to a wealthy few.

In the past, you likely would have had to pony up $250,000 -- on the low end -- to invest in a large commercial real estate deal.

By contrast, CrowdStreet's minimum investment is $25,000. Investors on the platform typically invest an average of $50,000, often spread between two or more projects or deals, Steen said.

And unlike the days when deals were struck over a round of golf, today all investment data and deal terms are easily accessible on the Web site for all investors to review.

"Everyone has the same information at their fingertips," Steen said.

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