1. J. Joe Ricketts, TD Ameritrade - $12.5 million

T2. Sheldon Adelson, Las Vegas Sands Corp. - $575,000

T2. Miriam Adelson, Adelson Drug Clinic - $575,000

3. Ending Spending, Inc. - $176,000

4. Financial Education and Advisory Initiative, Inc. - $100,000

5. C. Kevin Landry, TA Associates - $49,000

*Top donors for 2012 election cycle; numbers through Nov. 26, 2012.

Source: Center for Responsive Politics, Federal Election Commission