Why Amazon could be the next black swan for the market

Published 16 Hours Ago Updated 14 Hours AgoCNBC.com

Amazon appears untouchable.

It's rallied 37 percent this year, outperforming the market nearly fourfold. And a stunning quarter, reported last month, prompted nearly two dozen firms to up their price targets on the e-commerce giant; a handful of those newly minted price targets place the company north of the $1 trillion threshold.

But at this juncture, I suspect a black swan has taken flight. Just consider the stock's presence in so many passive vehicles.

An overwhelming passive presence

Amazon is a top holding in over 140 exchange-traded funds. A liquidity event for Amazon shares — perhaps triggered by issues related to the Trump administration's ordered reviewof the company's impact on the U.S. Postal Service — would create uncontrollable selling, in our view.

Zooming in further, around 40 ETFs hold Amazon within the top 5 percent. Look out below: This is a colossal failure of common sense.

A passive overdose

Investors have been stuffing themselves on a Thanksgiving feast full of technology stocks. Today, tech sector equities comprise nearly 30 percent of all large-cap mutual fund portfolios; this is an accident waiting to happen.

This represents the largest "overweight" relative to traditional benchmarks, relative to other large-cap sectors, in two decades. This represents, too, nothing more than a passive overdose on big tech, setting up large downside risk.

This development causes me to hearken back a decade.

Of course, who could possibly forget the great gorging on the financial sector heading into the crisis? Leading into 2007, banks and insurance companies comprised nearly 24 percent of the S&P 500. Today, the tech sector's large market weighing puts it up near 26 percent of the market's total capitalization.