So-called smart-beta strategies have overrun the world of equity exchange-traded funds as investors seek ways to spice up their boring old index funds. Now a pair of new bond ETFs from IndexIQ are getting into the act by adding a little "momentum" to their portfolios.

Earlier this month IndexIQ, which is owned by MainStay Investments, released the IQ Enhanced Core Bond US ETF (AGGE) - Get Report  and the IQ Enhanced Core Plus Bond US ETF (AGGP) - Get Report .

The AGGE tracks the IQ Enhanced Core Bond U.S. Index and is actually an ETF of ETFs, holding other bond funds including the iShares iBoxx $ Investment Grade Corporate Bond ETF (LQD) - Get Report  and the Vanguard Intermediate-Term Corporate Bond ETF (VCIT) - Get Report .

The AGGE carries an expense ratio of 34 basis points and yields 2.9%. It seeks to outperform the U.S. dollar-denominated, taxable, fixed income universe by using a momentum strategy that is measured by comparing a short-horizon (45-day) moving average of returns to a longer-horizon (90-day) moving average of returns, while taking into account recent volatility of each sector.

The AGGP follows a similar strategy, yet adds high-yield and emerging market debt ETFs to the mix. The AGGP can allocate up to 25% in U.S. high yield debt and up to 5% in U.S. dollar denominated debt of emerging market issuers. The net expense ratio for the AGGP is 35 basis point and the yield is 2.6%.

"Momentum is something that has been used in the equity space, as well as commodities and currencies for a long time," said Salvatore Bruno, chief investment officer for IndexIQ. "We are basically taking that and applying that to different sectors of the U.S. investment grade, non-taxable portion of the fixed income market."

Bruno said he expects IndexIQ to keep up its own momentum by introducing similar smart-beta bond ETFs in coming months.