Amazon is on the hunt for a new media buying agency to handle its global work. According to people familiar with the situation, the $136 billion Seattle-based ecommerce giant has issued a request for proposal for an agency tasked with duties for the brand's worldwide account.

Last year, Amazon spent more than $920 million on measured media in the U.S. alone, up 7.9% from 2015, according to Kantar Media. The company is focusing on increased international expansion in markets such as India.

A spokesman for Amazon did not return calls requesting comment. Adweek reported the news earlier on Friday.

All holding companies are participating in the review with the exception of Omnicom, which handles the business of rival Google, according to sources. IPG Mediabrands' Initiative is the global AOR for Amazon, which also works with MEC. An Initiative spokesman referred requests for comment to the client.

On Thursday, Amazon reported a 25% increase in second-quarter sales to $38 billion, though earnings, at $197 million, failed to meet analyst expectations. Investors sent the company's shares down in response, snatching away CEO Jeff Bezos' title of Richest Man on Earth in the process. The company, which recently announced it will acquire Whole Foods for $13.7 billion, said that marketing expenses are on the rise, led by an increase in Amazon's sales team, whose numbers rose 42% in the second quarter over the year-earlier period.

In recent weeks, Amazon has made a host of announcements including the launch of its own social network, Amazon Spark, and a new in-house accessories fashion line, the Fix. Sales on its annual Prime Day July shopping holiday were up 60% this year over 2016.