A late wave of buying helped nudge US stock indexes slightly higher Friday after a day of mostly listless trading. Banks and health care stocks climbed the most as investors priced in an increasing likelihood that interest rates will rise in the coming months. ‘‘The real takeaway here is if the Fed is willing to start moving, they see the economy as not only doing better but likely to do better going forward,’’ said Brad McMillan, chief investment officer at Commonwealth Financial Network. The increased likelihood of higher interest rates gave several stocks a modest lift, including banks, which stand to make healthier profits from lending as rates rise. Not faring as well were real estate, utilities and phone company stocks, which tend to lose favor among yield-seeking investors when interest rates rise.