While the Federal Reserve has predicted four interest-rate hikes this year – some, though, are now skeptical about a March change, safe-haven demand could continue to bolster Treasury bonds.

Meanwhile, Vanraes has short positions in U.S. two- and five-year notes at the same time as he is long 30-year Treasuries. Some investors may be less enthusiastic about short-term debt as the Fed gradually raises benchmark rates, and bullish on long-term debt as volatility, slow rate hikes and overseas demand help support U.S. debt on the other end of the yield curve.

Year-to-date, the iShares 1-3 Year Treasury Bond ETF (NYSEArca: SHY), Schwab Short-Term U.S. Treasury ETF (NYSEArca: SCHO) and Vanguard Short-Term Government Bond ETF (NYSEArca: VGSH) have all gained about 0.3%.

iShares 20+ Year Treasury Bond ETF

Max Chen contributed to this article.