Talk about keeping it 100.
The Nasdaq 100 index, which largely tracks large-cap tech stocks, rose to a new high on Thursday.
What's striking is just how un-unusual this now is. In fact, as of Thursday's close, the index has hit record highs in 9 of the past 11 sessions.
The Nasdaq 100 also has logged gains in 24 of the past 30 sessions, for an incredible 80 percent win rate.
"The market is suffering from an extreme case of 'FOMO' — this is a clear case of 'fear of missing out.' Everyone wants to be in, and nobody wants to miss out," Chantico Global CEO Gina Sanchez diagnosed Thursday on CNBC's "Trading Nation."
In other words, the string of positive sessions and the index's striking 21 percent gain this year have led more and more investors to jump in.
"People feel comfortable buying tech stocks, and ultimately that's what's leading this market higher," IITrader's chief market strategist, Bill Baruch, said Thursday on "Trading Nation." Investors "worry about selling out of good positions, so no one wants to sell, and people just keep buying higher."
Yet there's a downside to comfort that verges on complacency.
"Once the market does start to correct, you will see a big fear, and that's going to overexaggerate a move to the downside," Baruch added. He says he wouldn't be surprised to see a 10 percent drop that brings the Nasdaq 100 back to its late March lows.
Sanchez made a similar point, saying that with valuations at their highest levels since the dot-com bubble, "we could definitely see a retracement of where we've been."
The Nasdaq 100 is tracked by the PowerShares QQQ Trust, which is the largest tech-focused ETF by market value. Like the underlying Nasdaq 100, more than 40 percent of the QQQ is made up of five stocks – Apple, Microsoft, Amazon, Facebook and Alphabet.
Despite the strong start to Friday's session, the Nasdaq 100 turned sharply lower in midday trading.