Under normal market conditions, the fund will invest substantially all of its assets, and may invest up to 100% of its assets, in high income securities ("High-Income Securities"). High-Income Securities are fixed-income securities that Loomis Sayles believes have the potential to generate relatively high levels of current income. It may invest approximately 20% of its assets in investment-grade fixed-income securities. The fund may invest a portion of its assets in senior floating-rate loans made to U.S. and foreign borrowers.