NASHVILLE, Tenn. — Republican Randy Boyd’s campaign said he has brought in $2.3 million and added $2 million of his own money in his bid for governor, the biggest fundraising haul so far in the open 2018 race.

The former state economic development chief finished June with $3.5 million in cash left, his campaign said Monday. More than 1,500 donations have come in from all 95 counties, the campaign added.

Boyd said putting in his own money keeps his pledge to cover all overhead and operational costs so that donations from others can go toward voter contact and advertising.

“When we began the campaign, we mapped out a detailed budget plan, and like any good business person likes to see, I am happy to report that expenses are below budget, and our donations are significantly above initial projections, so I am proud of our team for managing the campaign so efficiently,” Boyd said in a news release.

Boyd wasn’t alone in tapping his personal wealth in the early stages of an already crowded race to succeed term-limited Republican Gov. Bill Haslam. Boyd founded Radio Systems Corp, a privately held company that makes invisible fences and other pet products and has annual revenues of about $400 million.

Williamson County Republican businessman Bill Lee said he raised about $1.4 million for the race. Lee and his wife matched that amount with personal money. He is chairman of Lee Co., which provides plumbing, electrical and HVAC services for residential, business and government customers.

Lee, who entered the field in late April, finished June with $2.5 million remaining.

“The response has been so overwhelmingly positive, we felt compelled to match the donations in an effort to thank everyone for their support and show our continued commitment to them throughout this campaign,” Lee said in a news release.

State Sen. Mae Beavers, a Mt. Juliet Republican who entered the race early last month, has raised short of $37,000. She also transferred $20,000 from her Senate campaign account, leaving her with about $55,400 cash left at the end of June.

And state House Speaker Beth Harwell, a Republican from Nashville, just joined the race this weekend.

On the Democratic side, former Nashville Mayor Karl Dean’s report shows he raised $1.2 million and entered July with $992,900 cash remaining.

Dean’s campaign has said it had received more than 3,000 contributions since Dean formally entered the race in March, with all but 3 percent coming from within the state.

Monday marked the deadline for state candidates to file more-detailed campaign finance reports covering mid-January through June.