In a letter sent to shareholders, Amazon.com Inc.'s founder and chief executive, Jeff Bezos, defended the online retailer's corporate culture, which was the subject of a critical report by The New York Times last year.

Bezos noted the enduring nature of corporate cultures in his annual letter to shareholders.

"The reason cultures are so stable in time is because people self-select," he wrote. "Someone energized by competitive zeal may select and be happy in one culture, while someone who loves to pioneer and invent may choose another," he said, adding that Amazon has never declared that its approach is the "right one."

Amazon was the subject of a months-long investigation by the Times, which depicted the company as having a bruising corporate culture that edged out workers who had been evaluated harshly by their peers and managers.

The online retailer forcefully rebutted the paper's report after it was published last year, with the company's top spokesman, Jay Carney, taking the unprecedented step of writing a public letter to defend Amazon and revealing personnel information about a former employees quoted in the story.

In his letter to shareholders, Bezos also trumpeted the success of big bets like the company's cloud computing arm, Amazon Web Services, and its wildly popular membership program, Prime. Amazon does not disclose membership data of its flagship Prime service, but analysts say it may have more than 40 million members in the United States.

In highlighting the speed at which Amazon launched services like Prime Now, its one- and two-hour delivery service, Bezos signaled to shareholders that the company was not done making bold investments in new business areas.

"Used well, our scale enables us to build services for customers that we could otherwise never even contemplate."