GoPro's stock has now more than doubled since its trading debut last week, gaining 20 percent on Tuesday alone. But Massocca points out that other momentum names also rallied, like Netflix, up more than 7 percent after a recommendation, and Vipshop, up more than 4 percent.
"It's indicative of the euphoric momentum we're in for the market. I keep hearing about this unloved rally. Unloved by whom? Everybody who is long loves it," said Peter Boockvar, chief market analyst at Lindsey Group.
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Janney Montgomery chief investment strategist Mark Luschini said he does not see the big round 17,000 marker on the Dow as that meaningful and said some investors may stay away for fear the market has gotten too rich.
"It will probably act as further paralysis for them to do anything, just as it was when it hit all-time highs. That made them think they should not act because it was too late," he said. "It's expressed in some circles among financial advisors. They're reticent to do it—take that gun shy client into the market and then have the market correct."
As stocks rallied, bonds sold off, with the 10-year yielding 2.57 percent from 2.52 percent Monday. Traders said there was some asset reallocation trades, but bonds also weakened as ISM manufacturing data showed strong new orders, China manufacturing data picked up, and the U.S. auto industry sold a much greater number of cars than expected in June.
"I think stocks have gotten expensive again. I don't think a bear market will start, but I think we're susceptible to an event that will drive stock prices lower," Massocca said.
Boockvar said he's watching the Russell, which broke through to a new high of 1,213.55 and then closed lower. The Russell is the hot tip of the market and includes many momentum names.
"If it fails here, and I don't know that it will, it would be a classic double top. Momentum can beget momentum and it can stay overbought," he said.
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Traders are also gearing up for Thursday's report of June nonfarm payrolls, expected at 212,000 from 217,000 last month. ADP's private sector employment report is released Wednesday at 8:15 a.m., and factory orders are released at 10 a.m.
"Mortgage applications are tomorrow, and everyone's excited by this pickup in housing. If it's not confirmed by the mortgage applications, it tells you there's still a very bifurcated housing market," Boockvar said.
Fed Chair Janet Yellen gives a speech at the IMF at 11 a.m. Wednesday and participates in a discussion with IMF Managing Director Christine Lagarde at 11:30 a.m.
"She'll just continue to say she's worried about the slack, and she'll keep rates lower for longer. It shouldn't be anything new," Boockvar said.
But traders will watch Yellen's words anyway, as the market continues to anticipate the end of the Fed's quantitative easing bond buying program and speculates when the Fed may move to raise rates.
"It still amazes me that we're three meetings away from the end of QE and nobody cares," said Boockvar.