According to John Kosar, director of research at Asbury Research, three charts show that a peak in stocks may already be underway.
Kosar first looks at the Nasdaq 100 index. He notes that it failed to break above its September 2000 high of 4,147.19. While the Nasdaq 100 made a few attempts to rise above that level this month, it still has not done so and closed Wednesday at 4,073.57.
"Markets have a long-term memory," he said. "Whenever you are bumping up against a big area like this, most of the time you're not going to get through it the first time. … Just looking at this chart all by itself, it suggests there's going to be a problem just getting through here, at least first try."
Kosar then looks at a chart of the assets in the ETF tracking the Nasdaq 100 (which trades under the ticker symbol QQQ). That chart just traded below its 21-day moving average, potentially spelling trouble for the overall index.
"When you're looking to see if a market is going to break a level, the thing you've got to realize is the horsepower that gets it there is asset flows," Kosar said. "And these asset flows are starting to pull in a little bit. In other words, people are doing exactly what you would expect them to do when you're at a 14-year high—they're taking some profits."
Since assets are declining, there's an increased chance of a meaningful downturn, Kosar said.
But it's not just charts of the Nasdaq 100 ringing bells for Kosar. The S&P 500 also has a particularly interesting pattern. Since 1957, Sept. 16 is on average the best day of the month for the broad market index. For the two weeks after that date, it tends to be "a slow move down into a strong selloff at the very end of the month," he said.
"Whenever I'm looking at these indicators, I don't want to look at [just] one," Kosar added. "I want to look at three or four different ones that are giving me the same answer. And all three of these are telling me to be careful here."
To see the full interview with John Kosar on what's ahead for the markets, watch the above video.