Microsoft routinely passes on details of security flaws in its own software to the National Security Agency (NSA) before it has produced and issued patches to users of its software around the world.
The news partly confirms widely held suspicions that Microsoft left "back doors" in its operating system software to enable US security services to hack into the systems of countries and companies overseas - both for state-led and industrial espionage to glean technology secrets.
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According to Bloomberg, thousands of US companies in technology, finance and manufacturing are working closely with US intelligence agencies, providing sensitive information on the one hand, while receiving classified intelligence on the other.
"These programs, whose participants are known as trusted partners, extend far beyond what was revealed by Edward Snowden, a computer technician who did work for the National Security Agency," according to Bloomberg.
Microsoft is one of the companies singled out by Bloomberg, but it is not the only one, according to the report.
Microsoft spokesman Frank Shaw claimed that the company released the security information about its software so that government agencies could make "an early start" on risk assessment and mitigation. However, Microsoft neither asks, nor is told, how the tip-offs are used.
Bloomberg's report follows interviews with a number of NSA insiders.
Security software vendor McAfee, which is now owned by semiconductor giant Intel, was also alleged to co-operate closely with the NSA, as well as the FBI and CIA. It is valuable to the US security forces not just because of the view it can provide of internet traffic, but also the possible espionage operations of foreign powers.
"Such a relationship would start with an approach to McAfee's chief executive, who would then clear specific individuals to work with investigators or provide the requested data, the person said. The public would be surprised at how much help the government seeks," the sources told Bloomberg.
The UK's Royal Navy submarine fleet uses a supposedly "hardened" version of Windows to run its command systems.
The revelation follows claims by a former defence contractor, Edward Snowden, that a number of US technology companies routinely handed over data about users to the NSA.
