More Fannie Mae and Freddie Mac shareholders are arguing that the structure of the Federal Housing Finance Agency is unconstitutional and are calling for courts to vacate the third amendment that sweeps the profits of the mortgage giants into the Treasury Department. Within the past month, two new cases have been introduced in Michigan and Minnesota, likely piggybacking on last year’s decision in which the single-director structure of the Consumer Financial Protection Bureau was found to be unconstitutional. Several shareholders of the government-sponsored enterprises filed...