With all due respect to the late, and great, Tom Petty, when it comes to today's stock market averages, it's "the weighting that is the hardest part."
It's been widely noted that the mega-cap technology stocks, from Apple to Amazon and from Microsoft to Facebook, are so heavily weighted in the Nasdaq Composite and the S&P 500, that they have driven those average to new all-time highs, even as the average stock remains down over 3% for the year-to-date.
The mega-caps, account for well over a quarter of the market value of the S&P 500, and even more of the NASDAQ, a concentration of gains we haven't seen since the height of the internet bubble in late 1999 or the energy bubble in the early 1980s.
What's odd about this potential inflection point is that the gains accrued to these stocks occurred in the midst of a pandemic and recession, not in a run-away bull market based on underlying euphoria that typifies love for a particular asset class.
In a very strange way, these stocks all gained value because they not only survived the pandemic but thrived in it, as well.
Amazon, Walmart, Apple and other, more speculative investments, like Tesla and Zoom, were either direct, or indirect, beneficiaries of the fear bubble that kept people home, where these companies were best suited to serve them.
On Wednesday we got a very strong taste of what happens if a medicine emerges that reverses the on-going spread of the Coronavirus and brings us closer to normal and farther from home.
Johnson & Johnson's good news on the launch of Phase III trials for its "one-shot" Corona vaccine sent "stay-at-home," "work-from anywhere" stocks reeling … which, by the way, also happen to be the aforementioned mega-cap names.
Certainly, the accelerating spread of the virus in Europe caused some concerns, but that was not evident in European markets on Wednesday. They were up until Wall Street turned down.
So, then, is it possible that good news will be very bad news for the "stay-at-home" stocks and, if so, will their extremely heavy weighting in the major averages cause a bear market on Wall Street?
Even if other groups take up the slack on the prospects for some return to recovery and normality, they are not nearly weighted heavily enough in the major averages to offset heavy losses in the mega-cap names.
In other words, will we see the emergence of a raging bull market in a wide variety of beaten down names that, quite simply, no one will notice? It's a critical question not just for Wall Street but for Main Street and Washington, as well.
A bear market in the most over-valued, heavily weighted sectors of the stock market could propel the Fed and the federal government to take additional actions to stimulate the economy, even if, in real terms, just as the economy is picking up steam. At the same time, stocks could appear to be telling quite another tale.
That recovery would be masked by the drop in big names, but it would also mean that people are going to malls, restaurants, movie theaters, staying in hotels again and getting on planes, trains and automobiles. It would be an interest trade-off that benefits Main Street much more than Wall Street. It will take some time to determine if we are, indeed, on that course.
Whether it's J&J's vaccine, or that of another company, an effective therapeutic that allows us to roll the behavioral calendar back to 2019, the answer to these questions will take some time. But it is interesting to note that, for the first time in history that I can recall, a recession could end with a bear market and not begin with one.
Looking at the Nasdaq Composite already down 12% from its record high because of the September pullback in tech stocks, this idea shouldn't seem that far-fetched.
In the meantime, Tom Petty's literal words are entirely spot on … for the next several months as we hope for the best, the waiting will indeed be the hardest part.
—Commentary by Ron Insana, a CNBC and MSNBC contributor and the author of four books on Wall Street.