Amazon, facing potential criticism of its plan to buy Whole Foods Markets, continued its multi-million lobbying effort - shelling out $3.2 million in the second quarter of this year - an increase from the $2.9 million spent in the first three months.

Amazon has long had a presence in Washington, lobbying on a broad range of topics ranging from taxes, immigration, trade and mobile payments.

But their decision, announced in June, to buy premium grocer Whole Foods for $13.7 billion roiled the grocery industry and has sparked some opposition on Capitol Hill and among unions and other Amazon critics.

That said, most antitrust experts expect the Federal Trade Commission to approve the planned merger.

Complicating the company's status in the nation's capital, Amazon founder Jeff Bezos bought The Washington Post - a newspaper that has drawn the public ire of Donald Trump.