Market's rally mainly Fed-inspired: Cashin

Yellen more dovish than expected: Cashin

The Federal Reserve's decision to maintain interest rates on Wednesday has helped grease the wheels of the market's rally, said UBS' Art Cashin, with Greece's debt woes largely being ignored.

The central bank held interest rates steady at their crisis-era levels, and suggested the economy—while softer—was on a path to recovery. Although Fed officials' forecasts suggest a rate hike may come by year's end, market watchers say the pace of any eventual tightening is likely to be gradual.

"The market is reinterpreting what it saw yesterday as either a one and done or maybe still a none and done," said Cashin. "The Fed is being seen as far more bullish."

Read More Fed leaves interest rates unchanged

Princeton Securities Group's Ben Willis also said he was not looking for a breakout.

"The bull is not dead and we have a way to go," said Willis. "Once we finnaly pull the band-aid off and get why we are fixated on normalizing rates."

Read More What bubble? Nasdaq closes at record as stocks rally on dovish Fed

Art Cashin
Adam Jeffery | CNBC

At least for the moment, investors certainly seemed to agree. The closed at 5,132.95, up 68.07 points. The S&P 500 and indexes also closed higher. The Fed's super-easy monetary policy has been a major factor behind the stock rally, some analysts say.

However, Cashin warned the downside loomed just around the corner, based on historical patterns.

"Tomorrow there is a chance for a record volume. Downside is the week after the June expiration has a history of a negative bias."