Even after a tumultuous year, the S&P 500 ended 2015 nearly flat. However, technician Jonathan Krinsky says stocks won't be so fortunate in 2016.
Markets kicked off the new year with a steep sell-off, with major U.S. indexes falling about 1.5 percent this week. But even as the S&P 500 has stalled, Krinsky pointed to weakness in the broader S&P 1500 index as a warning sign for large-cap indexes.
"We're moving sideways overall, but the internals are weakening. Nearly half of the S&P 1500 is down 20 percent from its 52-week highs, so you could almost say that half the market is already in a bear market here," the MKM Partners technician said Tuesday on CNBC's "Futures Now."
Another bad sign, Krinsky said, is the absence of a "Santa Claus rally" at the end of 2015.
"Since 1985, there have been just seven negative Santa Claus rally periods, and for four of the seven years, the next year was down and that included two of the bear markets in 2000 and 2008," he said.
And while Krinsky said history provides more of a guideline than a hard-and-fast rule, the addition of internal weakness will weigh even more on the S&P 500 this year. The major U.S. index has been making lower highs and lower lows in recent months, he said, a sign that large-cap stocks are following smaller-cap stocks down.
Krinsky said the next level of support for the S&P 500 comes in around 1,870, a 7 percent drop from where the index traded on Tuesday. A break below that could mean an even more drastic plunge for stocks, he said.
"If we get to the 1,870 level and we don't see a meaningful rebound with breadth and volume off that level, you're probably looking at something with a 17 handle on the S&P," Krinsky said Tuesday.
A drop to, say, 1,799 would represent a 10.7 percent drop for the S&P 500.