Despite this week's minor pullback, stocks still look solid on the surface. But a deeper look inside the market shows signs the bull is starting to crack.
Entering Friday's session, 200 components, or 40 percent, were in correction territory. A stock or an asset class enters a correction when it falls at least 10 percent from its 52-week high.
Among the stocks in a correction were e-commerce giant Amazon.com, Goldman Sachs, Exxon Mobil, Starbucks and Netflix.
Below is a table highlighting the S&P 500 components that are in a correction.
The U.S. stock market has already posted strong gains for the year, with the S&P advancing about 10 percent in that time. Leading the charge higher in 2017 has been the tech sector, which is up more than 20 percent year to date.
However, there are more signs of an internal breakdown.
Jonathan Krinsky, chief market technician at MKM Partners, pointed out in a note Thursday that less than 60 percent of stocks in the Russell 3000 are trading above their 200-day moving average, a key long-term technical metric.
"The Russell 3k represents 98% of U.S. equities. Bulls don't want to see this hold under 60% for too long," Krinsky said. "While not all negative divergences lead to negative outcomes, we are seeing enough of them to warrant some caution as we enter the worst part of the calendar."