Progressive kept its firm grip on the top spot in Media Monitors' Spot Ten Radio rankings for August 4-10, holding steady while other advertisers made big moves to get some last back-to-school dollars and promote the colder days ahead.

The week's biggest headline belongs to Pfizer, which rocketed from 57th to fifth, suggesting a major national push into flu shot season. They sit back-to-back with Johnson & Johnson's Tremfya, which has been a high ad spender lately.

Another notable mover is Lenovo, jumping back into the ninth spot as back-to-school season kicks into high gear. Rounding out the week's surprises is the professional 3-on-3 basketball league, BIG3, debuting in tenth.

ZipRecruiter climbed to second, and Upside settled into third, while T-Mobile surged from tenth to fourth.