The winner of the prize is scheduled to be announced in Stockholm at 1pm. Americans have enjoyed an unbroken run of wins in the economics category since 2000.
Last year, the honours went to Edmund S. Phelps for his analysis of long- and short-term trade-offs in macroeconomic policy.
The world's leading betting and gaming company Ladbrokes has for days seen Swedish economics professor Lena Edlund as the most likely winner, before American Christopher Sims.
If Edlund whose research mainly deals with the status of women was to be chosen, she would be the first women to be awarded the prestigious prize. She would also be the first Swede to win a Nobel since Bengt Samuelsson won the Medicine Prize in 1982.
In economic circles Jean Tirole of France, an expert on game theory, has also been cited repeatedly.
The Economics Prize was created in 1968 by Sweden's central bank and first awarded the following year.
All other Nobel prizes were first awarded in 1901.
Laureates will receive a gold medal, a diploma and 10 million Swedish kronor ($1.53 million) from Swedish King Carl XVI Gustaf, to be shared between them in each category, on December 10.
The exception is the Peace Prize, which is awarded at a ceremony in Norway in the presence of King Harald. On Friday, the 2007 Nobel Peace Prize was jointly awarded to former US vice president Al Gore and the Intergovernmental Panel on Climate Change "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change".