Gubernatorial candidate Jared Polis is outpacing opponent Walker Stapleton by continuing to infuse his campaign with millions of his own money.

Polis’ campaign has raised $13.1 million total since he started running, most of that his own money. Stapleton’s campaign, in comparison, has raised $2.38 million so far.

Polis, a Democratic congressman, will face off with Republican opponent and State Treasurer Stapleton in the governor’s election. Campaign filings submitted this week underscore the differences in resources that the candidates have.

Polis emerges from the primary race with a significant war chest. He reported $1.26 million cash on hand at the end of July. Stapleton reported $301,811 cash on hand.

Campaign filings for the last period, which covers June 28 through July 27, show Polis gave his campaign $1.6 million in July. That brings his total giving to $12.87 million for the campaign.

During that same reporting period, Stapleton reported receiving $255,067 in contributions.

Polis, one of the 10 richest members of Congress, has made a fortune in internet business ventures. He has used his wealth to tout his independence, saying he won’t take donations that are greater than $100 from individuals or accept anything from political action committees.