Here's something worth watching: nearly 35% of S&P 500 stocks—that's roughly 175 companies—are now trading in bear territory. Haven't seen numbers this ugly since May.

Rewind to last year through November? That figure was hovering closer to 20%. Fast forward to now, and the spread's widening noticeably. Market breadth is clearly tightening, and fewer stocks are pulling the index higher. Classic warning sign or temporary rotation? Time will tell.