The Union government will raise at least Rs 12,400 crore through the sale of five per cent stake in Oil and Natural Gas Corporation (ONGC), giving it a much-needed cushion in the run-up to the Budget. The government would sell 427.77 million shares at a floor price of Rs 290 through the recently introduced auction mechanism, the company said in a notice to the stock exchanges. The auction will be held during trading hours on March 1.