A bipartisan group of senators warned the government caretaker of Fannie Mae and Freddie Mac Thursday not to allow the two bailed-out mortgage giants to move any closer to rejoining the private market, saying that allowing the companies to operate the way they did before the financial crisis would be “counterproductive.”

Six senators, including Bob Corker, R-Tenn., and Mark Warner, D-Va., wrote to Federal Housing Finance Agency Director Mel Watt to warn him against re-privatizing the two companies, as that would “perpetuate the pre-crisis practice of socializing losses and privatizing gains.”