The JPMorgan High Yield Fund - R4 (JRJKX) is a mutual fund that focuses on investing in high-yield, or "junk," bonds. This fund is managed by JPMorgan and aims to provide investors with a higher level of income through its portfolio of lower-rated, higher-risk bonds. The "R4" designation indicates that this fund is designed for retirement accounts, making it a suitable option for those looking to diversify their retirement portfolio with potentially higher returns.