Some $12 billion will be spent this election cycle on political advertising to influence your vote. Much of the money will go to broadcast TV, internet companies and radio -- but where does it come from?
Unlimited contributions from so-called dark money groups means that big money in politics can run into the billions of dollars, and it is often undisclosed.
These groups are allowed to either support or condemn candidates, and they work independently, with no coordination with the candidate or the candidate's campaign. Huge expenditures on television advertising, social media and sometimes even films can help these dark money groups sway voters.
The money spent by these dark money groups often exceeds the candidates' own spending, and there have been seven such races in the 2016 election cycle, according to the Center for Responsive Politics.
Because such groups allow an unlimited supply of money to flow into the political system, they face huge criticism.
And though super PACs are legally bound to publicly disclose their list of donors, dark money groups have no such legal obligation.
Of all the money spent in election cycles in 2016, most of the dark money, or a total of $23.3 million, has been spent on the presidential race, with $20 million raised to campaign against Republicans.
Undisclosed and unlimited campaign contributions can be funneled through dark money groups to super PACs, and a lack of transparency and accountability allows such groups to thrive during election cycles. In some cases, organizations tend to partially disclose their donors, but that is purely by choice.
The total outside funding by undisclosed donors (excluding the party committee) this year is about $60 million, according to the Center for Responsive Politics.
This year, dark money funding from political non-profits such as 501(c)s, special interest groups and unions, special is 12 times the total amount in 2006.
Here is a look at the different groups.
1. 501 (c) groups
These organizations operate without any tax liability and can disclose their financial activities long after they have occurred. Further, the non-disclosure allows even a highly politically driven organization to shield its true description.
Social welfare groups under 501(c)(4) have the largest total spending under the category of 501(c) with $40 million in the 2016 election cycle. So long as politics isn't their primary function, groups such as these continue to thrive during election periods.
Following the controversial 2010 Citizens United Supreme Court case, spending by social welfare groups under 501 (c)(4) rose from $97 million in 2010 to $257 million in 2012.
The top two dark money groups crossing the $10 million mark are the U.S. Chamber of Commerce and the American Future Fund, both 501(c) organizations.
The U.S. Chamber of Commerce under section 501(c)(6) has reported political spending of about $20 million to the Federal Election Commission, with $8.4 million to be used against Democrats and $11 million in favor of Republicans.
The American Future Fund under 501(c)(4) has close to $19.3 million in campaign spending, with $16.3 million to be used against Republicans.
Big donors sometimes create deceptive corporations so that the donating can be done through them. By getting around the disclosure laws, such corporations can channel unlimited funding from undisclosed sources.
About $68 million has been funneled into the political system through such corporations in the 2016 election cycle, according to an analysis by The Washington Post.
Although many of these corporations are identifiable, others are formed under fake identities and addresses.
An example is the address 1209 North Orange St. in Wilmington, Del., which has been home to more than 285,000 companies, including Fortune 500 ones. Legal loopholes allow companies to register in havens that allow tax evasion.
LLCs simply list their offices in Delaware, which doesn't tax them on their profits. Dark donations from such LLCs remain complicated because they are un-mapped and many times untraceable.
3. Super PACs
These are allowed to accept money from dark money groups such as 501(c), LLCs and trade unions. In such cases, they don't have to disclose the donor's identity or the source of the contribution.
Critics argue that even the groups that disclose the list of donors don't act in real time. Through exorbitant expenditures on advertisements, phone banks etc., dark money groups are allowed to advocate for or against a candidate through Super PACs.
The undisclosed spending by dark money groups can either benefit or damage the image of a political candidate. In such cases, voters can be swayed, based on what they see and perceive within a limited period of time.