While the financial industry makes good money selling what is new, like IPOs, investors themselves very likely do better by sticking with the old: old companies, that is.

In an age of technological wonders and unicorn valuations for companies with little or no profit, investors can easily fall into the trap of overweighting new and buzzy companies and sectors.

The data tell a different story, with older companies actually outperforming the young, and really old ones, like a century or more old, doing exceptionally well.

U.S. initial offerings in 2015 were a bit of a bust, generating an overall loss of 2.1 percent for the year, according to Renaissance Capital data. And 2015 was not an aberration: earlier studies have shown that newly listed companies have underperformed the broader market in more than seven in 10 years since the early 1980s.

Contrast this to the performance of very elderly companies, which Credit Suisse called 'centenaries' in a recent study. Credit Suisse constructed a global index of 100-year-old-plus companies in historically stable industries like food, utilities and transportation and found quite strong results:

"Although historical share price performance statistics are no guarantee of future performance, we find it interesting that the 'centenaries' have an exceptionally strong track record. These 'old' companies have outperformed global equities by circa 500 bps annually since 2005 and by almost 300 bps during the past 12 months," Credit Suisse analysts wrote in a client note.

The New York Stock Exchange's Century Index, comprised of $1 billion-plus capitalization U.S. companies which are at least 100 years old, has also done well, outperforming the Dow Jones industrial average since its inception in May 2012 and, back tested, also outperforming major indexes going back to 2000.

To be sure, the underlying causes of this outperformance of the aged are hard to know with certainty, much less if they will persist. Yet one thing stands out, unlike IPOs or the kind of recently hot companies which are forever being featured on financial television, old companies are not really sold aggressively to investors.

That's in part because they often, being utilities or breweries or train companies, don't have an exciting new story. It is also because old companies aren't money machines for Wall Street. They simply require less investment banking. That leads, perhaps, to an imbalance of coverage tilted toward hot new sectors, and maybe even a bit more optimism about them in that coverage than is warranted.

James Saft is a Reuters columnist.