The 527 group American Crossroads has enjoyed a flood of donations since GOP strategists Karl Rove and Ed Gillespie launched it in late March, with two more million-dollar contributions collected in August.

Trevor D. Rees-Jones, president of Dallas-based Chief Oil & Gas, donated $1 million, as did Robert B. Rowling, owner and chairman of the private investment group TRT Holdings Inc. of Irving, Texas, according to a disclosure report filed with the Federal Election Commission.

American Crossroads collected $2.6 million overall in August while spending $772,597. It has compiled a tidy war chest of more than $7.1 million, with just weeks to go until the midterm Congressional elections on Nov. 2.

Of the nearly $8 million the group has raised overall, almost all has come from fewer than 10 wealthy donors and corporations.

American Crossroads is currently running TV advertisements against Senate Majority Leader Harry Reid (D-Nev.). It also disclosed spending more than $400,000 to support Rob Portman, a budget director for President George W. Bush, in his bid against Democratic Lt. Gov. Lee Fisher for Ohio’s open Senate seat.