Although Fannie Mae issued a record-breaking $47.36 billion in mortgage-backed securities in May, the company was scolded by analysts for only growing its mortgage portfolio at an annualized rate of 5.2 percent. "The [May] results show that Fannie Mae has outperformed our expectations for MBS issuance, but under-performed our expectations for building the mortgage portfolio," David Graifman with Keefe, Bruyette