Private markets for stocks and bonds have been growing faster than public markets, and that trend will continue, according to Daniel Gorfine, director for financial markets policy at the Milken Institute, and Ben Miller, co-founder of Fundrise investment platform.

The result could be fewer options for the average investor, they write in The Wall Street Journal.

Stock and bond issuance in the public markets dropped 11 percent in 2010 from 2009, to $1.07 trillion, while private issuance soared 31 percent, to $1.16 trillion, according to Security and Exchange Commission (SEC) data.

Editor's Note: The ‘Unthinkable’ Could Happen — Wall Street Journal. Prepare for Meltdown

The trend will probably intensify when the SEC implements the Jumpstart Our Business Startups Act, Gorfine and Miller say. It allows companies issuing securities privately to accredited (wealthy) investors to advertise more widely.

That means more growth of private markets, as companies avoid the regulatory hassles of going public, the duo writes.

“It could also mean fewer investment opportunities for the general public.”

To be sure, not every missed opportunity is a good opportunity. For example, non-accredited investors can’t invest in hedge funds.

But the average hedge fund returned just 6.2 percent in 2012, according to Hedge Fund Research, compared with 16 percent for the Standard & Poor’s 500 Index.

“A lot of funds were puzzled by where the market was going last year and were afraid to go long or short," Howard Eisen, managing director at Conifer Group brokerage, tells CNNMoney.

Editor's Note: The ‘Unthinkable’ Could Happen — Wall Street Journal. Prepare for Meltdown