That's not quite correct. 4.313 is the benchmark rate and they pay a little less than that depending on the actual balance. For example, between $10,000 and $100,000 they pay benchmark minus 1/2% which is 3.813%. On the first $10,000 I don't think they pay any interest.Quote from TempusFugit:
Not only do they pay, the current rate is 4.313% (!), much higher than, say, thinkorswim.