WASHINGTON ― Billionaire Donald Trump will be sworn in as the 45th president of the United States on Friday with hundreds of thousands in attendance. Before and after the swearing-in, governors, federal and state lawmakers, and many others will party at dozens of inaugural balls across the Washington, D.C., area.

It’s a tradition for states to have their own balls, where politicians and officials from both sides of the aisle will party. It’s also a tradition for these balls to be funded by large corporations and the lobbying firms they hire to push their agendas in Congress and state capitols.

This year, at least 14 state inaugural balls or events during inauguration week are funded or otherwise supported by corporations and lobbying firms.

Trump has promised that he will “drain the swamp” and end the outsized influence of lobbyists in Washington, much as President Barack Obama vowed when he entered office. Trump said he would keep lobbyists off his transition team. But in the end, the next president appointed both active and recently deregistered lobbyists to senior transition roles. When he held a controversial phone conversation with Taiwan’s prime minister, he was actually taking action orchestrated by a lobbyist for a foreign government.

Now with the inaugural balls, corporations with Washington interests are playing a key role again.

Oil and gas companies looking for significant rollbacks of environmental regulation from both Congress and the Trump administration are among the most notable funders of inauguration festivities.

Chevron is a sponsor of the Michigan and Texas inaugural balls. Exxon Mobil, whose former CEO Rex Tillerson is Trump’s nominee for secretary of state, is also sponsoring the Texas ball. So is the American Petroleum Institute, the main lobbying arm of the oil and gas industry.

The American subsidiary of BP, the British oil company, is a sponsor of the Texas and Indiana balls. Indiana is, of course, the home state of incoming Vice President Mike Pence. Automakers Ford, Honda and Toyota ― an industry that has garnered a lot of Trump’s attention recently ― are among a long list of other sponsors of Indiana’s event.

Iowa’s inaugural ball ― which will be attended by many of the state’s senior Republicans, including Gov. Terry Branstad, Lt. Gov. Kim Reynolds, Sen. Joni Ernst, and Reps. Steve King, Rod Blum and David Young ― is sponsored by the DCI Group, a major lobbying and public relations firm that counts Exxon Mobil as a client. The firm is also tied to the telecommunications industry, helping run campaigns opposed to net neutrality in Washington and against the provision of municipal Internet in cities, towns and other localities.

Koch Industries, the giant corporation run by billionaire conservatives Charles and David Koch, is helping out the Georgia, Oklahoma and Texas balls. The Koch brothers operate perhaps the largest political influence machine on the right, funding political advertisings, grassroots activism, college courses and inside-Washington lobbying.

Aside from Koch Industries, Oklahoma’s party is paid for by two natural gas companies that engage in the controversial practice of fracking: Continental Resources, run by generous Trump donor Harold Hamm, and Devon Energy, which has made large donations to Oklahoma Attorney General Scott Pruitt, Trump’s pick to run the Environmental Protection Agency.

Silicon Valley ride-share company Lyft signed up as a sponsor for the Michigan, Illinois, Texas and Tennessee balls by offering discounted or free rides to the events. Lyft and rival Uber have been lobbying in state capitols across the country for laws more favorable to their app-based taxi services.

"Lyft" your way to the @TNStateSociety's VolunCHEERS! .@lyft is an official sponsor of the event - code: VOLUNCHEERS and VOLUNCHEERS25 pic.twitter.com/E8fxdrpG46 — TN State Society (@TNStateSociety) January 11, 2017

Major law and lobbying firms are grabbing the opportunity to make nice with powerful politicians, too.

DLA Piper is sponsoring the Michigan ball. Dentons and Squire Patton Boggs have sponsored the Georgia celebration. The Indiana event is supported by Faegre Baker Daniels. Mayer Brown is a Texas ball sponsor. And the Alaska State Society is partnering with Jack Ferguson & Associates to hold an inauguration open house at the lobbying firm’s offices.