The $6 million sum—underwhelming for a top-tier presidential candidate—brings Rubio’s cash on hand to about $11 million. His campaign has raised roughly $18 million from nearly 100,000 donors since launching in April, according to the figures provided.

The relatively low figure is another sign of the summer-long dominance of “outsider” candidates like billionaire Donald Trump, who is self-funding, and retired neurosurgeon Ben Carson, who raised a whopping $20 million in the third quarter. The most recent primary polls place Trump first and Carson second in the Republican field.

Carson took in a whopping $20 million in the third quarter, an astonishing figure for a political neophyte. Kentucky Senator Rand Paul, the only other Republican in the race to release third quarter figures so far, raised just $2.5 million.