Fannie Mae and Freddie Mac will cost taxpayers $73 billion through 2021, nearly half of what they’ve pulled from the Treasury Department so far, according to President Obama’s 2012 budget released Monday. So far, the government-sponsored enterprises have pulled $131 billion in financial support from the Treasury Department. Its estimate of the ultimate cost net of expected dividends is less than the Federal Housing Finance Agency estimated in October 2010, when it said the two could cost between $221 billion in a best-case scenario and $363 billion if the economy recedes again through 2013. Banking analysts at Credit Suisse estimated a $321 billion price tag for the bailout of Fannie and Freddie. The Treasury Department released a white paper Friday outlining options for how to wind down Fannie and Freddie. Obama’s budget proposes “to gradually reduce the investment portfolios and size and amount of loans guaranteed by Fannie Mae and Freddie Mac and ending the conservatorship of these companies.” Fannie Mae’s current mortgage portfolio stood at $788.7 billion in December, the latest month of data. It’s up 2% from a year before. It peaked in May 2010 at $813.6 billion and has fallen every month since. Freddie Mac’s investment mortgage portfolio was at $696.8 billion in December, actually down 7% from a year ago. It has decreased every month since April 2010. “The administration will work with the Congress to pursue reform of the system that best fulfills these principles while engaging a wide range of stakeholders,” Obama said in the budget. Write to Jon Prior. Follow him on Twitter: @JonAPrior