When Bill Gross looks in the mirror, what does he see?

In his latest monthly "Investment Outlook" commentary, the Pimco chief waxes philosophical. He questions whether he and other legendary investors are really all they're cracked up to be. Maybe guys like Warren Buffett, George Soros, and Ray Dalio were just lucky guys in the right place at the right time.

In questioning initially whether I am a great investor, I open the door to question whether other similarly esteemed public icons like Bill Miller are as well. It seems, perhaps, that the longer and longer you keep at it in this business the more and more time you have to expose your Achilles heel—wherever and whatever that might be. Ex-Fidelity mutual fund manager Peter Lynch was certainly brilliant in one respect: he knew to get out when the gettin' was good. How his "buy what you know best" philosophy would have survived the dot-coms or the Lehman/subprime bust is another question.

So time and longevity must be a critical consideration in any objective confirmation of "greatness" in this business. 10 years, 20 years, 30 years? How many coins do you have to flip before a string of heads begins to suggest that it must be a two-headed coin, loaded with some philosophical/commonsensical bias that places the long-term odds clearly in a firm's or an individual's favor? I must tell you, after 40 rather successful years, I still don't know if I or PIMCO qualifies. I don't know if anyone, including investing's most esteemed "oracle" Warren Buffett, does, and here's why.

Investing and the success at it are predominately viewed on a cyclical or even a secular basis, yet even that longer term time frame may be too short. Whether a tops-down or bottoms-up investor in bonds, stocks, or private equity, the standard analysis tends to judge an investor or his firm on the basis of how the bullish or bearish aspects of the cycle were managed. Go to cash at the right time? Buy growth stocks at the bottom? Extend duration when yields were peaking? Buy value stocks at the right price? Whatever. If the numbers exhibit rather consistent alpha with lower than average risk and attractive information ratios then the Investing Hall of Fame may be just around the corner. Clearly the ability of the investor to adapt to the market's "four seasons" should be proof enough that there was something more than luck involved? And if those four seasons span a number of bull/ bear cycles or even several decades, then a confirmation or coronation should take place shortly thereafter! First a market maven, then a wizard, and finally a King. Oh, to be a King.

But let me admit something. There is not a Bond King or a Stock King or an Investor Sovereign alive that can claim title to a throne. All of us, even the old guys like Buffett, Soros, Fuss, yeah – me too, have cut our teeth during perhaps a most advantageous period of time, the most attractive epoch, that an investor could experience. Since the early 1970s when the dollar was released from gold and credit began its incredible, liquefying, total return journey to the present day, an investor that took marginal risk, levered it wisely and was conveniently sheltered from periodic bouts of deleveraging or asset withdrawals could, and in some cases, was rewarded with the crown of "greatness." Perhaps, however, it was the epoch that made the man as opposed to the man that made the epoch.

The epoch that drove the returns of our investment kings, Gross says, has been an era of credit expansion. The real test for greatness will come as a new epoch dawns.
If the epoch of credit expansion is permanently over, will these guys be able to continue to perform?

PIMCO's epoch, Berkshire Hathaway's epoch, Peter Lynch's epoch, all occurred or have occurred within an epoch of credit expansion—a period where those that reached for carry, that sold volatility, that tilted towards yield and more credit risk, or that were sheltered either structurally or reputationally from withdrawals and delevering (Buffett) that clipped competitors at just the wrong time—succeeded. Yet all of these epochs were perhaps just that—epochs. What if an epoch changes? What if perpetual credit expansion and its fertilization of asset prices and returns are substantially altered? What if zero-bound interest rates define the end of a total return epoch that began in the 1970s, accelerated in 1981 and has come to a mathematical dead-end for bonds in 2012/2013 and commonsensically for other conjoined asset classes as well? What if a future epoch favors lower than index carry or continual bouts of 2008 Lehmanesque volatility, or encompasses a period of global geopolitical confrontation with a quest for scarce and scarcer resources such as oil, water, or simply food as suggested by Jeremy Grantham? What if the effects of global "climate change or perhaps aging demographics," substantially alter the rather fertile petri dish of capitalistic expansion and endorsement? What if quantitative easing policies eventually collapse instead of elevate asset prices? What if there is a future that demands that an investor—a seemingly great investor—change course, or at least learn new tricks? Ah, now, that would be a test of greatness: the ability to adapt to a new epoch.

In short, the time for testing is now