An unusual business model for the mortgage industry United Wholesale operates under a different business model than competitors such as Rocket (NYSE: RKT) or PennyMac Financial Services (NYSE: PFSI). The stock would rocket as investors calculated how many shares the mutual funds tied to that index would need to buy in order to properly track it. This is due to investor fears that interest rates will rise by a lot next year as the Fed tightens to quell inflationary pressures.