Ad technology company Trade Desk Inc. (TTD.US) may face the risk of losing one of its most important clients, Wal-Mart (WMT.US). Sources revealed that the retail giant renegotiated its cooperation agreement with Trade Desk Inc. last year and now has the option to use other companies' advertising buying platforms.

Under the previous four-year agreement, Trade Desk Inc. was the exclusive technology service provider for advertisers who utilize Wal-Mart's customer data for online advertising campaigns. These advertisers leverage this data for precise ad targeting.

The report indicates that this move could benefit direct competitor Amazon (AMZN.US). Amazon has recently intensified its efforts in handling online advertising sales and is offering incentives to advertisers to encourage them to abandon the Trade Desk Inc. platform.

Sources revealed that Trade Desk Inc.'s high fees have caused dissatisfaction at Wal-Mart, prompting them to renegotiate the partnership. According to relevant sources, Trade Desk Inc. charges Wal-Mart's advertising clients double-digit rates for using the technology. In contrast, Amazon charges advertisers only 1%, a reduction from previous rates of 5% and 7%.

A Trade Desk Inc. employee revealed that Wal-Mart keeps strict control over customer shopping data to prevent it from falling into Amazon's hands. The employee stated that Trade Desk Inc. has built an independent version of its technology for Wal-Mart, which operates on Microsoft's Azure platform, although most of its business still relies on Amazon's cloud service platform AWS.

Another person familiar with Wal-Mart's thinking indicated that the retailer might also achieve this goal by acquiring an existing advertising buying platform or simply building its own advertising buying platform from scratch.