Investors expect a 50 basis point cut and a major factor in increasing global risk appetite.
However, economists who favor a 25 basis point cut say the current state of the U.S. economy does not justify a larger move.
Stock movements
The stock market index rose. Saudi Arabia The benchmark rose 0.3 percent, helped by a 4.3 percent rise in Saudi First Bank.
The main stock index fell in Dubai 0.1 percent, affected by a one percent decline in the shares of leading real estate developer Emaar.
In Abu Dhabi, the main index closed down 0.1 percent.
Prices fell Oila catalyst for Gulf financial markets, after two sessions of gains following an industry report showing an increase in crude and fuel inventories in the United States.
Outside the Gulf region, the blue-chip index rose in Egypt 0.6 percent, with Ezz Steel shares jumping 9.1 percent.