A single bid for the much-sought-after C block accounted for nearly $3 billion of that $6.1 billion total in the eighth round, the final round of the day. The bid of $2.976 billion was for a package of eight licenses serving all 50 states.

Earlier in the day, in Round 6, a single bidder for those eight C-block licenses had lost out to several bids in a number of the geographic regions in the C block, but a single-package bid took dominance by the end of the day. It is possible that multiple C-block bidders could re-emerge, but it is unclear who is bidding, because the FCC does not disclose the names of bidders. Names of winning bidders won't be disclosed until the auction ends, perhaps in a month.

The status of the nationwide D-block bidding remains the same since the first round, when a single bid for $472 million was entered. That band of spectrum would be paired with another band for public-safety uses.

Bidding resumes Tuesday, and the public can monitor the results of each round at the FCC site.