Spending is surging in the election to represent Colorado’s 5th state Senate district as Republican candidate Marc Catlin surpasses his opponent, Democrat Cole Buerger, by about $35,000 in the most recent reporting period.

The coin-toss race, which could determine whether Democrats gain supermajorities in both chambers of the General Assembly, is being closely watched by both Democrats and Republicans, with political groups from both sides also ramping up their investments.

Residents in the district are likely to be bombarded with mailers and digital and TV advertisements as the candidates have spent more than $100,000 to get out their messages. 

Outside groups have also spent more than $1.7 million in the race so far. As of Thursday, the race had drawn the most state-level super PAC spending in Colorado, according to The Colorado Sun. The high spending is another indicator that both parties believe they stand a chance at winning the seat. 

In the most recent campaign finance reporting period — from Sept. 26 to Oct. 9 — Catlin spent nearly $42,000. That’s almost two-thirds of his total spending this year. In that same period, Buerger spent $7,000.

Excluding the most recent reporting period, Buerger was the candidate using the most funds this year, outspending Catlin by about $14,000 from January through September. That includes spending during the primary election. As of Friday, Catlin had spent about $67,000 and Buerger had spent $46,000. 

The bulk of Catlin’s spending in the latest period, about $25,000, was spent on direct mail and digital advertising. Another $11,000 went to TV advertising. 

Buerger’s spending in that period largely went to consulting services. 

The group All Together Colorado, the state Senate Democratic campaign arm, has spent $426,000 supporting Buerger or opposing Catlin. 

The group’s Republican counterpart, Senate Majority Fund, has spent $1.2 million.

The spending is likely to intensify in the final weeks until Election Day on Nov. 5. Buerger has more funds remaining with about $66,000 in the bank compared to Catlin, who has about $54,000.

Ballots have been mailed out and residents can track theirs online at BallotTrax.ColoradoSOS.gov.