Mortgage rates for a second home are also typically 0.25% to 0.50% higher than the rate for a primary residence, said Garth Graham, senior partner at Stratmor Group, a mortgage advisory firm. The rate is usually 0.50% to 0.75% higher for an investment property.

Cook responded to Pulte in a statement, "I have no intention of being bullied to step down from my position because of some questions raised in a tweet."

The Trump administration has levied mortgage fraud accusations on other high-profile Democrats–especially Trump critics.