Goldman Sachs boosted its year-end forecast for the Standard & Poor's 500 Index to 1,750 from 1,625 previously.

The new prediction represents a 5 percent gain from Tuesday's record close of 1,669.

U.S. economic strength and global central bank easing will propel the increase, Goldman analysts say.

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"If interest rates stay low despite better growth, then upside to S&P 500 may be greater than we currently forecast," David Kostin, Goldman's chief U.S. equity strategist, writes in a commentary obtained by CNBC.

"Monetary easing by the [Federal Reserve, Bank of Japan and European Central Bank] keeps sovereign yields low and would support this potential outcome."

Buoyant dividend growth will also boost the market, Kostin notes. He expects the strongest dividend increases to come in the information technology, financial services and consumer discretionary sectors.

Meanwhile, Sheila Patel, head of international operations at Goldman Sachs Asset Management International, sees a twist on the idea of the "great rotation" into stocks from bonds.

"Perhaps the best name is not the 'great rotation' but the 'gradual rotation,'" she tells CNBC. "If you look at the state of investment today and asset allocation, it has taken years, not just since the financial crisis, to get to the current asset allocation."

She notes that fund flows have been particularly strong in the last two weeks.

"If you look at the last week or two fund flows have been very strong into equities but out of cash, and also going into bonds at a lower rate," Patel explains. "In the U.S., there is always a positive sentiment towards equities underlying, and so there is some ability to move there too."

Others agree with Kostin that the Fed's easing will keep stocks percolating.

"We have a long stretch now with no significant decline, and I think that's going to continue until there is some significant concern about the Fed stopping," Jason Thomas, chief investment officer of Aspiriant, tells Bloomberg.

Editor's Note: The Final Turning Predicted for America. See Proof.