Indian investors looking for better returns and to diversify from equities are lapping up high-yielding but riskier corporate bonds as demand for domestic debt rises. Funds raised by issuing low-investment grade corporate bonds, rated ‘BBB-’, have surged over eightfold to Rs 15,419 crore so far this year, according to data from Prime Database. Debt rated below ‘BBB-‘ is considered non-investment grade.