The Information reported on Amazon's efforts to reduce its Oracle dependency in January. Analyst Brian White of Drexel Hamilton issued a note disputing the report, pointing to remarks Oracle Chairman Larry Ellison had made on the company's December earnings call.
"Let me tell you who's not moving off of Oracle," Ellison said. "A company you've heard of just gave us another $50 million this quarter to buy Oracle database and other Oracle technologies. That company is Amazon."
Ellison continued by noting that "competitors, who have no reason to like us very much, continue to invest in and run their entire business on Oracle."
An Amazon spokesperson declined to comment for this story. An Oracle spokesperson said in a statement that Amazon has spent hundreds of millions of dollars on Oracle technology, including $60 million about a year ago.
"We don't believe that Amazon Web Services has any database technology that comes close to the capabilities of the Oracle database," the statement said.
The two companies have been in a heated war of words. Last year Oracle executives boasted about the cost advantages of using its database software. AWS CEO Andy Jassy fired back a few weeks later in an interview with CNBC, saying that Oracle is "a long way away in the cloud."
The rivalry kicked off in earnest in 2014 after AWS introduced the Aurora relational database service, taking aim at Oracle's core market. Capital One, Expedia, GE and Verizon are among the companies now using Aurora, according to the AWS website.
AWS also offers a tool that allows businesses to move databases to the cloud. The Database Migration Service, which supports Oracle's software, has handled the transfer of more than 80,000 databases to AWS, Jassy said in July.
In a 2016 meeting with analysts, Ellison said that Amazon's cloud still wasn't ready for primetime, and that as Oracle's big customers moved to the cloud, they would push their databases to Oracle's services.
"Our database customers really can't run their machine-critical workloads at Amazon," Ellison said. "They can't do it."
But since then Oracle has failed to pick up notable market share in cloud infrastructure. AWS has a commanding lead in that market and is followed by Microsoft, Google, Alibaba and IBM.
Investors are now left guessing about the size of Oracle's cloud services, after the company last quarter stopped disclosing the amount of revenue it brings in from that business.
— CNBC's Christina Farr contributed to this report.