Pershing Square Capital Management, the largest holder of GSE common stock, is telling its shareholders to be patient with its investment in Fannie Mae and Freddie Mac, despite the drubbing the shares have taken this year. As Inside The GSEs went to press late this week, Fannie common was trading for $1.41 a share compared to a 52-week high of $3.31 and a low of $1.21. Freddie common was selling for $1.60. Its high for the year is $3.24, its low $1.20.