Markey also brought in nearly $2.2 million from lawyers and lobbyists, with his top overall contributor being DLA Piper, the top law firm that handles technology and energy clients, among others. PACs and individuals affiliated with DLA Piper contributed $133,100 to his campaign throughout his career.

The totals, first reported by the Boston Globe but collected by the Center for Responsive Politics, shed light on the strong fundraising muscle Markey has used to amass more than $12 million since 1989, and one that he'll continue to flex in his bid for Senate, if Sen. John KerryJohn KerryFormer Obama officials say Netanyahu turned down secret peace deal: AP How dealmaker Trump can resolve the Israeli-Palestinian conflict John Kerry to teach at Yale on global issues MORE (D-Mass.) is confirmed for secretary of State, as is expected.

Markey currently has about $3 million cash on hand ready for a bid. He'll also have the formidable fundraising powers of the Democratic Senatorial Campaign Committee, which endorsed him for the seat soon after he announced his intentions to pursue it.

Markey's position on the Energy and Commerce Committee helps explain the high number of donations from communications and electronics industries. That committee includes the Communications and Technology subcommittee, which oversees issues ranging from internet regulation to intellectual property laws.