Major stock indexes have hit record highs again this week, and Komal Sri-Kumar, president of consulting firm Sri-Kumar Global Strategies, says the market has entered bubble territory.

"My concern now is we're in the sixth year of monetary easing and still don't have economic growth pickup to a sustainable pace," he tells Yahoo. "We've done [easing] for a long period of time, and there's still no improvement for the growth picture."

The economy contracted 1 percent in the first quarter, and while many economists attributed the bulk of the downturn to bad weather, Sri-Kumar disagrees.

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"The economy showed a significant amount of weakness, that's what the bond market is referring to," he said. The 10-year Treasury yield stood at 2.62 percent early Friday, down from 3.04 percent Dec. 31.

"The bond yield should be going up to 3.50 percent to 3.75 percent rather than go down because you should be afraid of the Fed tapering. After the tapering has begun the bond yields have actually gone down," he explains. "So that says to me it's not so much the taper that is bothering the bond market, but it is the fact that economic growth hasn't picked up."

That move indicates a weak economy, and the stock market, is simply "taking advantage" of monetary stimulus. "There is a big bubble forming," Sri-Kumar notes. "It looks like it's getting into dangerous territory right now."

But that doesn't mean the bubble can't grow larger. "You can never tell how big it's going to get before it bursts."

David Kostin, chief U.S. equity strategist at Goldman Sachs, is a bit more bullish than Sri-Kumar is. Kostin thinks the S&P 500 will climb 2.9 percent through year-end — to 2,000 from Thursday's close of 1,930.11.

"The valuation of the market is at the higher end of a range of fair value, and it's pretty consistent with what we've seen, in terms of economic data, broadly speaking, getting better," he tells CNBC.

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