The downturn in the U.S. coal industry isn’t just hurting coal mining and coal-heavy power companies; it’s also having a devastating effect on the groups formed to help promote the industry—coal lobbyists.

Three of the most prominent coal lobbying groups have seen high-profile supporters drop off of their membership lists in recent years, and with them, the high-dollar donations given to fund political activities intended to support the coal industry.

A report released by the Climate Investigations Center—a group that monitors the energy and environmental policies of corporations, trade associations, and political organizations—noted that five of the seven major utilities that gave $1 million or more to the American Coalition for Clean Coal Electricity (ACCCE) in 2008 are no longer members of the group. DTE Energy—one of the big donors that dropped out—reportedly told the Climate Investigations Center: “With the transition of DTE’s energy generation resources to a more diversified fuel base, ACCCE no longer aligns with our business strategy.”

Six electric cooperatives have also been removed from ACCCE’s membership list, including three in the past year: Electric Cooperatives of Arkansas, Basin Electric Cooperative, and Sunflower Electric Cooperative.

Losing members has taken its toll financially. According to the report, ACCCE’s Internal Revenue Service filings showed total revenue of $53,733,277 in 2009, but revenue decreased to less than $20 million in 2014. That has drastically affected what the group has been able to spend. After devoting nearly $12 million to lobbying and political expenditures in 2011, the ACCCE had cut back to less than $2 million in 2014.

The two big donors from 2008 that still remain members of ACCCE are American Electric Power (AEP) and Southern Company. However, neither company seems to be supporting the group as it once did. According to AEP’s 2015 corporate political contributions chart, it paid $20,000 to ACCCE for lobbying last year. Southern Company reported that it contributed $100,000 to ACCCE in 2015 for political purposes—a far cry from the $2.1 million that the Climate Investigations Center said the company gave ACCCE in 2008.

Other coal lobbying groups are faring no better. The National Mining Association (NMA) and World Coal Association (WCA) have also both been losing members. PacifiCorp was the largest utility to leave the NMA in recent years, but other well-known supporters that have backed out include Chevron, CSX, Norfolk Southern, Volvo, and Wells Fargo. The WCA’s most notable loss was GE, but it has also seen prominent coal mining companies Consol Energy, Arch Coal, and Alpha Natural Resources head for the exit (although the last two probably ended their affiliations due to bankruptcy).

Aaron Larson, associate editor (@AaronL_Power, @POWERmagazine)