"My gut tells me: If the S&P were to rally another 150 points, what are you making, 10 percent? But if the S&P has a correction similar to, or more dramatic, to what happened in the Russell and the Nasdaq, I think the risk-reward is to the downside," he said. "I know people want to participate, but maybe there's a better opportunity coming up to get involved."
On CNBC's "Halftime Report," Altman of CBD Trading said he saw significant risk.
"We haven't had the capitulation rally that we had, like from '98 to 2000, but the market is, in my opinion as a macro look, is more risk to the downside than to the upside," he said.
Altman, speaking from the two-day SkyBridge Alternatives Conference in Las Vegas, Nevada, also said he saw the market as something as a toss-up.
"I see an enormous confusing market at the moment," he said, noting U.S. Treasury bond yields on the 10-year around 2.5 percent. "I see the damage they've done to the Russell and the Nasdaq, and yet the S&P's on all-time highs.
"It's a confusing time to trade, and I think the market really has to show itself before you can make some major decision on which way the market's going to go. And that's the way I've taken it lately. Are we going to have a correction? Are we going to have a move up? It's very hard to determine."
Altman said that he didn't expect global events, such as the situation in Ukraine, to have much of a lasting effect.
"I don't think the geopolitical is that big a deal, but it's concerning that the bond market is doing what it's doing," he said. "Sometimes things stay going in a direction before they change, and that may be the case right now."