



Trump finally hit the airwaves earlier this month with an ad focused on immigration, and so far has only spent about $5 million.



Clinton has reserved about $9.2 million in airtime this week.



The new investment comes amid signs that Trump's lagging poll numbers may be improving against Clinton's following a campaign reboot.



Trump senior communications adviser Jason Miller said in a statement that the billionaire businessman's "positive message of economic opportunity is working and we see the national and battleground state polls all moving in the right direction."



"With Hillary Clinton off the campaign trail yet again this week and continuing to take many communities' votes for granted, we see this as the right time to show voters the benefits of an American economy under the leadership of Mr. Trump," he added.