Many mortgage bankers are bracing for a slowdown in originations this year, but they have an even larger concern on their hands: whether Fannie Mae and Freddie Mac will hike their net worth minimum currently set at $2.5 million. The GSEs and their regulator have said little on the subject, but there is rampant speculation that it’s only a matter of time before higher net worth minimums are introduced – it’s just a matter of when,…