At the same time, short duration continues to be the default play as the U.S. Federal Reserve still attempts to cool down inflation further. They can serve as a passive income source or a cushion in the case of a volatile stock market (which, as alluded to earlier, tends to happen in the month of September). Versus a an ultra-short fund, this allows a fixed income investor to go farther out on the duration scale in order to extract more yield—its current 30-day SEC yield for that matter is 5.19%.