While most stocks have rebounded significantly in the wake of the financial crisis, tech investors have done especially well: Over the last five years, the tech-heavy Nasdaq Composite has risen nearly 100%, strongly outperforming the much more balanced S&P 500. With unprofitable social media darlings and cloud technology companies rewarding shareholders with outsized returns, concerns over a second tech bubble are surfacing.

"There is clear consensus that we are witnessing our second tech bubble in 15 years," wrote hedge fund manager David Einhorn in a letter to his investors earlier this year. Einhorn's fund, Greenlight Capital, is short a basket of high-flying tech stocks on the belief that the market is reliving a modest retread of the late 1990s.

But venture capitalist Peter Thiel disagrees. With about three-quarters of his net worth tied up in Silicon Valley start-ups, and most of his wealth a byproduct of successful tech ventures (PayPal and Facebook, among others) it's hard to see Thiel as a bastion of objectivity on the subject. But Thiel isn't dismissing the possibility of an economic bubble. Indeed, he embraces it, but believes investors looking for the bubble in tech are misguided.

In his new book, Zero to One (written with Blake Masters), Thiel discusses the factors that created the tech bubble of the late 1990s, and why today's environment is much different. In a recent telephone interview, Thiel told me where he thinks today's bubble lies, and why investors could be in for a rude awakening.

A recent history of bubbles
Thiel's libertarian leanings seem to have had a notable influence on his investing. The creation of PayPal, for example, grew out of a desire to replace the U.S. dollar with a new digital currency. More recently, Thiel's persistent donations to the Seasteading Institute -- a group dedicated to creation of floating cities free from traditional government control -- have often drawn headlines and invited controversy.

It's hardly surprising, then, that Thiel is critical of central banks. Though he doesn't claim to be a proponent of the so-called Austrian School of Economics, he does see some legitimacy in the notion that fiat money is inherently linked to financial instability.

We've had this very strange history ... this series of crazy bubbles for the last few decades. The Nikkei bubble in the 1980s in Japan. There was the tech [bubble] in the 1990s. There was the housing-finance bubble in the 2000s. It's possible that there's some strange link to fiat money and sort of getting off the gold standard in '71 that's led to this sort of financialized regime that's been prone to bubbles.

Spotting the next one
Since the financial crisis, investors have wondered if we're living through yet another bubble. Since 2009, bearish forecasters have proclaimed the imminent collapse of equities and the U.S. dollar. Thiel isn't so bold as to offer up an exact prognostication, but he does believe we are experiencing another bubble of massive proportions.

My candidate for the bubble today is ... centered on government bonds. There's something about [quantitative easing] policy, and the negative real interest rate policy, that's very unstable. I'm not sure exactly how or why it ends, but I have this sense that -2% real interest rates ultimately lead to enormous, bubble-like distortions. [We] are in this massive government bubble right now.

Preparing for the collapse in unlikely places
Thiel's belief in a government bond bubble isn't novel -- others have made the same claim for years. But many of those people have advocated for both traditional and esoteric "safe" havens such as gold, foreign equities, or farmland. Thiel's outlook is quite different.

Is there another bubble in Silicon Valley? The simple answer is there's no bubble in tech, because ... bubbles are a psycho-social phenomena -- the public is not involved. These IPOs are happening too late, so it's very different from the 1990s. ...The more elaborate answer is, I believe we have a much bigger bubble in government bonds. Probably three-quarters of my net worth is tied up in private, illiquid, tech stocks in Silicon Valley because that's one of the asset classes that's as far away from the government bond bubble as you can possibly get.

Unfortunately, most investors lack of the luxury of putting their money in such companies, but Thiel believes there are opportunities in the public markets. Although many might view investing in a company such as electric-car maker Telsa (NASDAQ:TSLA) to be an inordinately risky bet, Thiel believes it could -- paradoxically -- prove to be a safe haven.

There's a way in which the [Federal Funds Rate] impacts all assets, but it impacts assets differentially. ...The assets affected the most are the ones most like government bonds. So corporate bonds [for example], or maybe housing. ... On the equities side, the equities that are most like bonds -- the ones that pay high dividends, or these value stocks that have these very predictable cash flows -- those are the ones that sort of get modeled like bonds. The super high growth stocks -- the main variable is growth. ... So I think in a weird way, the tech growth stocks like Tesla, or the [software as a service] companies, or all the Silicon Valley stocks are actually the least distorted."

Safety can be deceptive
According to Thiel, investors sitting in stocks that are traditionally viewed as safe (such as utility companies, which he termed "government bonds in drag") could be most likely to suffer. Should the bond bubble burst, these stocks -- valued for their steady, bond-like cash flows -- could be hit the hardest.

Previous bubbles have certainly been built on the back of "no risk" propositions: In 2005, responding to claims of a burgeoning housing bubble, former Federal Reserve Chairman Ben Bernanke called the possibility of a correction in home prices an "unlikely possibility." Historically, housing prices had never gone down -- they were, at the time, considered the safest of assets. In contrast, tech stocks, then coming off the dot-com crash, were risky. Yet, investors who bought shares of Amazon.com or Google in 2005 fared far better than those that purchased homes.

Only time will tell if Thiel's views prove accurate. If he is right, the popular conception of what makes an asset "safe" will be challenged yet again.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.