Scott Caraher, head of senior loans at Nuveen -- manager of the Nuveen Floating Rate Income fund -- says that the higher-than-expected increase in rates that has driven up borrowing costs has made credit selection 'more important today than it has ever been.' He notes that lower-rated companies can't sustain high levels of interest payments for long levels of time. As a result, Caraher says he is underweight the lower-quality part of the market, wary of a pick-up in default rates; the flip side of the situation is an opportunity to overweight better-quality companies which are generating superior returns now and which will be more stable and solid whenever the Fed starts cutting rates int he future.