On Wednesday, Donald Trump filed papers and paid the $40,000 fee to qualify for South Carolina's Republican presidential primary ballot, a spokesperson for Trump's campaign confirms.

The payment — made a week before the September 30 deadline — is the latest sign that the poll frontrunner has no plans of wrapping up his presidential bid anytime soon.

The $40,000 fee to get on the ballot, split between the state election commission and the state GOP, is an unusually expensive one, and the deadline by which it must be paid is unusually early.

As such, it can contribute somewhat to the winnowing of this unusually large Republican field. Rick Perry, for instance, was having trouble coming up with the South Carolina money before he decided to quit the race earlier this month. (Scott Walker did pay the fee in August, but is also now out of the race due to money problems.)

The Republican candidates who have paid the South Carolina fee and qualified for the ballot so far include Jeb Bush, Marco Rubio, John Kasich, Carly Fiorina, Ben Carson, Ted Cruz, Rick Santorum, Bobby Jindal, Lindsey Graham, and Mike Huckabee. Rand Paul will reportedly file next week.

There are no reports yet of Chris Christie, George Pataki, or Jim Gilmore paying the fee. So if you're looking for who might be the next candidate to drop out, it could be one of them.