LQD has a 3.05% 30-day SEC yield and VCIT has a 3.03% 30-day SEC yield. Meanwhile, HYG has a 4.79% 30-day SEC yield.

“We’ve been cautious in high yield for a while now, and we saw a little shakeout at the end of June and into July,” Martin added. “We think a lot of investors are most likely moving too low in quality to get just a slight pickup in yield.”

Investors can also gain exposure to investment-grade quality international debt through ETFs, including the PowerShares International Corporate Bond Portfolio (NYSEArca: PICB), which has a 1.66% 30-day SEC yield, and the SPDR Barclays International Corporate Bond ETF (NYSEArca: IBND), which has a 0.82% 30-day SEC yield.

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

Max Chen contributed to this article.

Full disclosure: Tom Lydon’s clients own shares of LQD and HYG.