Five years ago today was when the market hit its intraday low of 666. Since then, the market has been on a bull run, defying the market bears who called for a pullback at every turn. But how long can it possibly continue?

In this segment of Monday's Investor Beat, host Chris Hill and Motley Fool analysts Matt Argersinger and Taylor Muckerman look at a recent statement from hedge fund manager Seth Klarman. His long tenured track record of market outperformance lends a lot of weight to his words, so when he says the market is entering bubble territory, it could definitely mean that looking more carefully at valuation today before buying a stock could be a prudent decision.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.