Amazon Web Services recently won a secret government cloud computing contract worth about $10 billion from the National Security Agency, an agreement that’s being challenged by Microsoft, Nextgov reports.

The contract, which is codenamed "WildandStormy," was not publicly announced, but Microsoft was informed of the deal in July, prompting the company to lodge a bid to protest with the Government Accountability Office. These filings revealed the code name and show that the deal is the second major cloud computing agreement that the U.S. intelligence community has made in the last year, after the CIA split its C2E contract between five companies, including AWS and Microsoft, as well as Google, Oracle, and IBM.

"NSA recently awarded a contract for cloud computing services to support the Agency. The unsuccessful offeror has filed a protest with the Government Accountability Office. The Agency will respond to the protest in accordance with appropriate federal regulations," a spokesperson for the NSA told Nextgov. 

A spokesperson for Microsoft confirmed that the company has filed a bid to protest the contract.

"Based on the decision we are filing an administrative protest via the Government Accountability Office. We are exercising our legal rights and will do so carefully and responsibly," they said.

AWS previously agreed to a $600 million contract to provide cloud computing services to the CIA in 2013, and later provided services to the NSA as well. Microsoft previously won the Pentagon’s Joint Enterprise Defense Infrastructure contract over Amazon, but their contract was cancelled last month following several years of legal wrangling.

Chris Cornillie, an analyst at Bloomberg Government, told Nextgov that this contract "just reiterates that Amazon is still the cloud provider to beat across the federal government. Microsoft has come a long way and made it a two way horse race in government, but Amazon was forming relationships and gathering security certifications a decade ago and Microsoft is still playing catch-up."

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