With interest rates still at uber-low levels, investors aren't taking any chances. The list of the most popular exchange-traded bond funds this year is dominated by those with only limited interest-rate sensitivity.

The biggest draw for net new cash through Oct. 30 was the $13.8 billion Vanguard Short-Term Bond ETF, according to IndexUniverse in San Francisco. Besides offering broad exposure to both government and corporate issues, the fund comes with an expense ratio of 0.10%, vs. an average 0.37% for US-focused bond ETFs, the research firm notes.