Amid the concerns of top financial donors that he's lagging too far behind in polls, Jeb Bush signaled on Monday that he's got plenty of money in the bank to stay on the campaign trail leading up to next year's early primaries.

The Bush campaign announced plans to reserve -- but not outright buy -- $7.8 million in television advertisement time in Iowa, New Hampshire and South Carolina in January and February. By reserving time, a campaign is able to lock in a certain ad rate in advance and get first dibs on the best time slots before other campaigns and super PACs try doing the same thing at a later point.

"As voters in early states and beyond get to know Jeb Bush’s record and vision, he is building support," said campaign press secretary Kristy Campbell. "Our campaign will have the resources needed to be competitive throughout the calendar, ensuring Governor Bush is the nominee."

State-by-state, the Bush campaign has reserved $1 million in air time in Iowa; $4.6 million in New Hampshire; and $2.2 million in South Carolina, she said.

The dollar figures reflect how the Bush campaign feels generally about the first three states: New Hampshire is the biggest priority and they like their chances in South Carolina more than in Iowa. In each state, Bush is currently lagging behind other GOP rivals, including Donald Trump, Ben Carson, Carly Fiorina and in some cases, Sen. Marco Rubio (R-Fla.).

The Bush campaign declined to say on Monday whether they've actually put the money down as a deposit on the air time or just reserved it. Each television station works differently, so the actual price of the air time could go up at a later date, requiring the campaign to spend more money.

Word of the advertising plans come as some of his top donors are warning that Bush needs to demonstrate growth in the polls over the next month or face serious defections among supporters.

Bush continues to battle against a steady decline in the polls, sinking to fifth place at just 7 percent in a national NBC News/Wall Street Journal poll released Sunday.

But the ad-time reservations announced Monday are part of the campaign's long-term approach -- and with the fundraising quarter ending on Wednesday night, the moves are a signal that the campaign has the necessary funds to remain active into the early weeks of next year.