Market uncertainty rules after Brexit vote, analysts say

U.S. stock futures rallied Tuesday after a two-day sell-off following the Brexit vote, but more headwinds are on the horizon and the market opportunities remain unclear, analysts told CNBC.

Stocks on major exchanges in Germany and London were up more than 2 percent and the pound rose nearly 1 percent. Still, market watchers remained cautious.

"The reality is there aren't a lot of great outcomes," Macro Risk Advisors CEO Dean Curnutt told CNBC's "Squawk Box" on Tuesday.

If a swift British exit from the European Union ushers in new barriers to trade, it would be negative for markets, he said. But a drawn-out Brexit would create uncertainty that could potentially drag down an already weak global economy, he added.

"The economics of Brexit, the sort of stalled nature of business investment, of business growth, I think that potentially feeds back into the real economy, even back into the U.S. economy," he said.

The outsized impact on European banking stocks seen in the last two sessions also presents the danger of financial contagion, he said.

Curnutt noted the S&P 500 (INDEX: .SPX) was trading just short of a new all-time high prior to the U.K. vote on Thursday. He said he worries stocks could still have much further to fall.

David Lebovitz, global market strategist at JPMorgan Asset Management, said it was too soon to tell whether value is being created amid falling equity prices.

The key issue for markets continues to be whether companies can finally produce earnings growth, and renewed dollar strength puts that in question, he said. A stronger greenback makes U.S. goods more expensive to overseas buyers, creating an obstacle for U.S.-based multinationals.

"In the background you have rising wages, and so I ask myself, is this going to be a headwind which materializes for U.S. profitability, at a time when the pre-existing headwinds were just beginning to subside?" he told "Squawk Box" on Tuesday.

The dollar's rise may also put pressure on the Chinese yuan once again, leading to further capital outflows, which roiled markets earlier this year, he said.

"I just feel like we're setting ourselves up for more of what we saw [at the] beginning of this year, last summer, where you see a lot of dollar strength, you see financial conditions tighten very quickly, and that leaves the Fed in a very difficult position, unable to normalize policy at the pace at which they would like," he said.

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