Senate Majority Leader Harry Reid’s latest haul of campaign cash included $114,000 in bundled contributions from lobbyists and political action committees, according to a newly required disclosure his campaign filed this month with the Federal Election Commission.

Under a new congressional ethics law passed in 2007, the Honest Leadership and Open Government Act, campaigns are required to report bundled contributions from lobbyists and PACs when they exceed $16,000. The reporting requirement kicked in this year.

In the first half of 2009, Reid’s No. 1 bundler was William Singer, a partner in the Chicago law firm Kirland and Ellis who hosted a Reid fundraiser there in June. He’s credited with $39,750 in bundled donations.

“Bundling” is when one campaign donor gets credit for getting a bunch of others to contribute, a la the “Rangers” of the George W. Bush campaign. Ethics hawks criticize the practice as a way of circumventing campaign-finance limits.

What exactly constitutes “bundling” is largely left up to campaigns to define under the new law. Essentially, anyone the campaign credits with bringing in multiple donations is a bundler.

Reid lists three more bundlers in addition to Singer: FMR Corp. PAC, the Boston-based parent company of financial firm Fidelity Investments, with $36,500; Emanuel Rouvelas, a lobbyist and partner in the firm K&L Gates, with $19,000; and another top D.C. lobbyist, Anthony T. Podesta of the Podesta Group, with $18,700.

The bundled donations total $113,950 out of the more than $5 million Reid raised from Jan. 1 to June 30 of this year.