A somewhat murky outfit called Specialty Group has become the election's biggest corporate donor, handing $5.3 million to a conservative super PAC over the course of 10 days last month. But that's about all anyone knows about the company, founded just a month ago and based in Knoxville, Tenn. Its business address is a private home, it lacks a website, and its lawyer—the only name linked to the company—has a disconnected phone number, NBC reports. A look at some of the other big-time super PACs and corporate donors:
                                    
                                    
                                
                                
                             
                            
                            
                            
                            
                            
                                
                                
                                    
                                        
 -  The second-biggest corporate donor is Oxbow Carbon, owned by William Koch, brother of David and Charles.
-  Third is Contran, a firm owned by Texas donor Harold Simmons.
-  Chevron is something of a rarity among Fortune 500 groups who are also major donors; it gave $2.5 million to a group linked to John Boehner.
 Some 85% of corporate cash went to Republican-allied groups, while 11% went to Democrat-affiliated organizations. But the biggest donations have come from businesspeople's personal coffers.