From Bangor Daily News:

“The campaigns of Collins and Gideon were among them, but the three biggest purchases belonged to the Republican dark-money group One Nation and Democratic dark-money groups Maine Momentum and Majority Forward, which have been the two biggest non-campaign spenders in the race so far. It brought total TV ad spending in the race above $9.5 million, according to [AdImpact] data. (It is only January. Here’s your soundtrack.)”