CNBC's Jon Najarian says market commentators who say President Trump's tax-reform proposal isn't priced in the market at all are wrong.

"It's in the market -- not 100%, but it's in the market, and it's been pushing more and more of the market since the Senate approved the budget," Najarian told TheStreet's Financial Success Strategies symposium over the weekend in New York. "If they indeed could do the rest of some sort of tax reform under reconciliation for whatever it is -- $1.5 trillion or whatever they have to stay under [deficit caps] -- if they can do something like that, I think that that's additional upside."

However, Najarian added that if Trump "tweets at too many people in his own party" and tax reform falls apart, that could be the catalyst for investors to start "hitting the exits or at least trying to hedge themselves very quickly."

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