1. Interest on reserves increases the rate of growth of commercial bank reserve balances held at the Fed: https://fred.stlouisfed.org/series/IORB

2. How Do Primary Dealers Make Money? Primary dealers buy bonds directly from the government and then resell them to clients and investors at a slight mark-up. This small difference in price is how primary dealers earn a profit. https://www.investopedia.com/terms/p/primarydealer.asp