Institutional investors remain largely bullish on U.S. equities for 2015. However, stock exchange traded fund investors should still temper expectations as volatility could dampen returns.

According to a recent NEPC survey, 96% of institutional investors are bullish on equities for the year, with 54% of respondents pointing to a 6% to 10% return, reports Mark Melin for ValueWalk.

Specifically, 36% of institutional investors believe U.S. equities will outperform in 2015 while 13% said emerging market equities could outperform.

ETF investors also have a number of options to capture the two markets. For instance, investors can use the SPDR Dow Jones Industrial Average ETF (NYSEArca: DIA), SPDR S&P 500 ETF (NYSEArca: SPY) and PowerShares QQQ (NasdaqGM: QQQ), which tracks the Nasdaq-100, to track the major U.S. benchmarks.

For broad U.S. market exposure, the Vanguard Total Stock Market ETF (NYSEArca: VTI), Schwab U.S. Broad Market ETF (NYSEArca: SCHB) and iShares Core S&P Total US Stock Market ETF (NYSEArca: ITOT) essentially cover the entire U.S. stock market in a single investment option.

However, investors should temper their outlook. Michael Feroli, chief U.S. economist at JPMorgan Chase, downwardly revised estimates of U.S. economic growth, reports Peter Coy for Bloomberg.