COLUMBUS, Ohio — It's nearly impossible to turn on the television and not see a political ad for Sen. Sherrod Brown or his opponent Bernie Moreno. The stakes are high as the winner will likely ensure his party will either keep or regain power in the Senate.
Both candidates are spending millions of dollars and that doesn't include tens of millions more from political action committees.
Brown and Moreno have turned the race for the U.S. Senate seat into one of the most expensive in the nation.
Sherrod Brown has a war chest of $51 million dollars. Moreno has raised a total of $15 million, which includes $4.5 million of his own money.
Ian Vandewalker studies elections for the Brennan Center for Justice.
"It is not true that whoever spends the most wins," he said.
Hundreds of millions of dollars of outside money are pouring into both campaigns. Sarah Bryner is research director at open secrets which tracks campaign spending.
"Moreno has particularly benefited hugely from outside spending i think so far this cycle we have around $45 million spent supporting him and then an additional $33 million in opposing Brown, so that's way more than Brown is getting," she says.
Data from OpenSecrets breaks down the top contributors for each candidate.
Brown's major supporters include the Retirement industry, democrats, lawyers, education and securities and Investment firms.
For Moreno, he's getting support from the retirement industry, securities and investment firms, Republicans, automotive, and the Real Estate sector. But this is money that can be tracked.
"There is money that is impossible to trace," Bryner said.
It's called dark money and it's mostly untraceable. It's playing a huge role in both campaigns.
"The opacity is there on purpose; to mislead to obfuscate the true source of money and to reduce the accountability that these groups have to the public," says Bryner.
10TV looked into the top Political Action Committees for each campaign.
Moreno's top contributor is Defend American Jobs, a super PAC affiliated with the cryptocurrency industry. It donated more than $30 million, according to the Washington Post.
"That is definitely an industry to watch to build influence in Washington, " Vanddewalker said.
The Senate Leadership Fund, affiliated with Senate Minority Leader Mitch McConnell, has spent more than $20 million on the Moreno, according to OpenSecrets.
The WinSenate PAC, a pro-democratic fund, spent nearly $20 million on advertisements attacking Moreno on behalf of Brown, according to OpenSecrets.
Because the race is so close, voters will continue to be inundated with political ads. But it's who is behind the ads that experts say voters should pay close attention to.
"I think it's important to keep an eye on who are these big industries [and] who are these ideological spenders, "Vandewalker said.
"Most folks when they see an ad on TV or on social media don't go beyond the message. In many cases, these messages are brought to you by dark money groups. In some cases we know who they are. In some cases, we don't but getting that information to the voters is a problem," Bryner said.