The US national debt ceiling has to be increased as the limits are reached. With a deficit at near or over 1.5 trillion dollars a year the debt ceiling more quickly tops out and Congress must pass a new higher borrowing limit. The national debt is near 14 trillion and growing therefore Congress will need to pass a new limit above 15 trillion dollars or face the legal inability for the US government to borrow. The US treasury sells bonds, notes and t-bills in auctions that financial institutions, foreign sovereign nations and individuals place bids on to purchase. The ones that are willing to accept the lowest interest payments win the auction and buy the debt issues.