The Koch brothers poured $301 million into politically-active groups in 2012, according to a report from the Center for Responsive Politics.
The T-shirt promoted the greeting “Merry Christmas” over “Happy Holidays.”
The agency had weighed regulations requiring companies to disclose certain campaign spending.
Treasury's move to limit nonprofit groups is unlikely to drive big donors out into the open.
Proponents call the commission's decision a temporary setback for the virtual currency.
The Democratic Senatorial Campaign Committee raised $4.8 million last month.
The president will hold a DNC fundraiser this month with "Friends" creator Marta Kauffman.
But the commission would prohibit campaigns from spending the virtual currency.
The Republican National Committee (RNC) raised $7.1 million in September, the committee said Sunday, slightly less than the $7.4 million netted by the rival Democratic National Committee (DNC) during the same month.
The Senate Conservatives Fund, a key backer of the Republican congressional effort to link the federal budget to defunding ObamaCare, netted more than $2.1 million in the month leading up to the government shutdown.
That total is the highest of the year for the conservative group, founded by former Sen. Jim DeMint (R-S.C.), and the second-highest monthly total it had ever reported. Some $1.9 million of that haul came from small donors.
Their "Don't Fund ObamaCare" petition and donation website was touted by top Republicans engaged in the fight to link ObamaCare to a government shutdown, including Sen. Ted Cruz (R-Texas). The organization helped Cruz defeat Lieutenant Governor David Dewhurst — a more centrist Republican — in the 2012 senatorial primary to replace former Sen. Kay Bailey Hutchison (R-Texas).