Despite the market rebound in January and growing optimism, more cautious investor can look to cash alternatives like ultra-short-duration bond exchange traded funds to hedge potential risks down the road.

According to a recent Bank of America Merrill Lynch survey, investors with $515 billion in assets are not convinced by the recent rally in the equity markets as they showed a preference for cash over stocks, Bloomberg reports.

The survey found that global equity allocations in February dipped to the lowest level since September 2016 even after U.S. markets experienced one of their best January start in years. The lack of exuberance suggests that a deep lack of conviction in the sustainability of the rebound among investors. For example, the percentage of investors who believe the S&P 500 Index peaked at 2,931 increased to 34% this month compared to 11% in September.

Many money managers shifted over to cash, accumulating a net allocation to 44%, their highest overweight since the 2009 financial crisis.

The “February fund manager survey shows a big rotation from equities into cash,” BofA strategists led by Michael Hartnett said in a note. It “does not show an improvement in investor sentiment; we say bearish investor positioning remains first-quarter positive for asset prices.”

The BofA survey found that allocations to U.S. stocks declined to the lowest in 9 months at 3% underweight, with U.S. equities being the second-least favored among money managers.

Investors who are seeking cash substitutes may look to actively managed, ultra-short duration bond ETFs that are more free to adapt holdings in a shifting market environment and generate a decent yield along the way.

For example, the PIMCO Enhanced Short Maturity ETF (NYSEArca: MINT) has a 2.95% 30-day SEC yield and a 0.26 year duration. The Invesco Ultra Short Duration ETF (NYSEArca: GSY) has a 2.90% 30-day SEC yield and a 0.37 year duration. The SPDR SSgA Ultra Short Term Bond ETF (NYSEArca: ULST) has a 2.80% 30-day SEC yield and a 0.32 year duration. The iShares Short Maturity Bond ETF(NYSEArca: NEAR) has a 3.05% 30-day SEC yield and a 0.52 year duration.

Potential investors should be aware that these active ultra-short-term bond ETFs include corporate debt exposure with some lower quality investment-grade debt exposure, which may have contributed to their relatively higher yields.

Additionally, investors can look at conservative short-duration Treasury bond ETFs, such as the iShares Short Treasury Bond ETF (NYSEArca: SHV), which has an effective duration of 0.40 years and 2.32% 30-day SEC yield, and the SPDR Barclays 1-3 Month T-Bill (NYSEArca: BIL), which has a 0.13 year duration and a 2.20% 30-day SEC yield.

For more information on the fixed-income markets, visit our bond ETFs category.