Below is a chart comparing the S&P 500 to the Nasdaq Internet Group since the start of 2013. As shown, after trending inline with each other over the first five months of 2013, the Internet group broke away from the S&P 500 in the second half of the year. The Internet group ran and ran and ran all the way to its highs this February, gaining more than 80% from where it started 2013. Over the same time period, the S&P 500 gained as well, but not nearly as much.
Once March rolled around, though, the fun for the Internet group ended. We've seen pure carnage in this group over the last two months, as names like Amazon.com (NASDAQ:AMZN), Netflix (NASDAQ:NFLX), Pandora (NYSE:P), Groupon (NASDAQ:GRPN), etc. have plummeted. Through Thursday, the Internet group is now up just 43.4% since the start of 2013, erasing nearly half of its 80%+ gain at its highs. As you can see in the chart, as the Internet group has been falling, the S&P 500 has been chugging along just fine, not gaining much, but not falling much either.
As it stands now, the Internet group is still outperforming the S&P 500 by roughly 12 percentage points since the start of 2013, but another week like this one where the momentum names tank and the broad market holds up, and the tortoise could catch up to the hare.