(Bloomberg) -- Treasuries snapped the biggest advance in a month before the Federal Reserve announces a decision today on whether it will slow asset purchases from $85 billion a month at the end of a two-day policy meeting.

The difference between two- and 10-year yields was 2.51 percentage points, versus an average 2 percentage points during the past year. Two-year yields are anchored by what the Fed does with its target rate, while 10-year yields are more influenced by the central bank’s debt-purchase program. Fed Chairman Ben S. Bernanke will hold a press conference in Washington after the decision. The U.S. plans to sell $35 billion of five-year securities today in the second of four note auctions this week.

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