Treasuries extended their strong November gains as traders weighed mixed US government debt sales amid speculation that the Federal Reserve is done raising interest rates.

Following a soft $54 billion sale of two-year notes, a $55 billion auction of five-year bonds saw strong demand. The benchmark 10-year yield has fallen by eight basis points to around 4.4%. Stocks struggled following a rally that sent the market into one of its biggest meltdowns in the last century, putting the S&P 500 near "overbought" levels. Industrial and financial stocks performed poorly. As Cyber Monday began, Amazon led gains among retailers.

This week's economic data will be closely watched by traders, including the Fed's preferred measure of underlying inflation. New home sales in the United States fell in October following a downward revision to the previous month, as decades-high mortgage rates weighed on demand. The November Fed Bank of Dallas manufacturing index was lower than expected.

Bets that policymakers are done raising interest rates have fueled a rally in the S&P 500 this month, lowering short-term volatility expectations. While some took advantage of the opportunity to buy protection on the cheap, it has been far from universal - and calls that the market environment is becoming too calm are on the rise.