It’s a private stock market shared by millionaires, celebrities and double-digit dividend yields.

This market is riddled with former government big shots… The Clintons, Mitt Romney, Al Gore, Rudy Giuliani and George H.W. Bush have all made millions in it. According to Bloomberg News, Bill Clinton made $15.4 million in this market between 2003 and 2007.

Warren Buffett, Goldman Sachs, George Soros and others have made billions from this private market, too.

…Yet I doubt your average investor has ever even heard of it.

That’s because for the most part, no one but the wealthiest 6% of investors has had access to this “millionaires only” market. But that’s quickly changing.

In fact, I predict that in 2015, this private market will open up to more investors than ever before.

Today, I am going to tell you about a way to tap into this premier market immediately and without having to be a millionaire.

I am talking about investing in business development companies (BDCs).

Similar to the double-digit yielding, “secret wealth” investments I talked about in a recent issue of Dividend Opportunities, BDCs give ordinary investors the ability to play in a higher risk/higher reward arena usually reserved for large institutions or wealthy venture capitalists.

These firms, which Congress laid out the rules for in 1980, operate similarly to private-equity firms: They find small, private businesses poised for growth and help them achieve it.

If promising companies with viable new business concepts are out there, you can bet that BDCs will be all over them. In other words, when you buy shares of a BDC, you’re investing in a portfolio of some of the world’s fastest-growing businesses… while they’re all still private.

BDCs operate with sky-high profit margins in mind. These firms loan money to smaller, “middle-market” private companies (with revenues between $100 million and $1 billion) to fund their growth. In exchange for these higher-risk loans, BDCs are able to rake in lucrative interest payments — typically at rates of 15% or higher — or even command an equity stake in the company being funded.

And when a company achieves its goals and the BDC decides it’s time to cash out (or if the company goes public), the payoff can be huge.

But here’s the best thing of all about BDCs: they pay huge dividend yields.

In fact, because of their “pass-through” tax structure, the law requires that BDCs pay out at least 90% of their profits to investors in the form of dividends. Many BDCs pay out up to 98% of their profits to avoid corporate taxation altogether.

As a result, it’s common for a BDC to pay three times the dividend yield of a typical S&P 500 stock. In fact, it’s not unusual to see 10%-plus yields from these companies (see the table below).

Of course, not all BDCs are created equal. So before you go chasing the highest-yielding BDCs, here are a few rules I use to evaluate a BDC to ensure the highest chance of success…

1. Focus on BDCs that make safe loans to strong businesses that are generating positive cash flows.

2. Look for BDCs that do the best job of managing risk by diversifying their holdings, with no one holding accounting for more than 15% of the total portfolio.

3. Focus on BDCs that are able to borrow at extremely low rates, as they can generate even more impressive returns on their investment.

4. Select companies that have strong insider ownership. A CEO whose net worth is tied to his stake in the company is a CEO who will act in the company’s best interest.

5. And lastly, seek out BDCs with a stable dividend history and a long-term track record of above-average share price gains.

Now, you won’t become a millionaire overnight by investing in BDCs. But with a modest portion of your portfolio to invest and a little research, you will be on the ground floor of one of the highest-yielding and exclusive markets in existence.

​Here’s something that can help you get started. In my latest report, “The Hottest Investment Opportunities for 2015,” I’ll tell you more about BDCs and even give you the names and ticker symbols of my five favorite BDCs right now — all of which are trading at big discounts and pay dividend yields from 6.2% on up to 10.4%. I should also add that in the past, regular investors who’ve invested in this “millionaires only” market have seen gains of 41%, 46% and 76% in less than a year. To learn how to get this report for free, follow this link.