FlexShares Credit-Scored U.S. Long Corporate Bond Index Fund LKOR is an investment-grade high-yield bond ETF, which yields 4.17% annually. FlexShares CreditScored US Long Corporate Bond ETF (LKOR): ETF Research Reports Wall Street was downbeat last week mainly due to Federal Reserve Chair Jerome Powell’s comments at the Jackson Hole economic symposium that the central bank will remain committed to fight inflation.