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Buying an edge: The high-tech race for economic data pays

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The once-sleepy process of releasing economic data has quietly gotten a lot more complicated, and a lot more lucrative, than many people might think.

Take the relatively obscure National Association of Realtors, which releases market-moving housing statistics such as existing home sales figures. Behind the scenes, the release process is a complicated mix of early disclosure involving both free media access and paying clients, each getting access to the data at slightly different times—although all are instructed to release it at the same time.

The association tells CNBC that it sells early access to its data as much as 90 minutes ahead of the official release time to two data service providers. But the association says those data service providers are held to a strict embargo and not allowed to retransmit the information to their own clients before 10 a.m., when the data goes out to the public.

(Read more: Investors are moving out of housing. Here's why)

The association also says it has three paying clients, one of which is "primarily" a trading firm, that buy access to the data at precisely 10 a.m.

A spokesman for the association declined to name any of NAR's paying clients, or to say how much they pay for access to the information, citing privacy concerns.

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"The clients who do receive on an embargoed basis get up to 90 minutes in advance, with release at Coordinated Universal Time using atomic clocks," NAR spokesman Walt Molony said in an email to CNBC.

Just when various market participants get access to potentially market-moving data has become a hot topic in financial circles in recent months.

In early July, New York State Attorney General Eric Schneiderman requested that data vendor Thomson Reuters discontinue its practice of selling access to market-moving consumer data to paying clients two seconds ahead of a broader release time, citing fairness concerns.

(Read more: NY AG's early data probe goes beyond Reuters)

In the NAR case, there is no such tiered access. Instead, the paying clients receive the data early, and are instructed not to retransmit it until the same time it is released publicly.

At that moment, the housing data becomes just one particle in a telecommunications arms race between high-speed trading firms looking to transmit and trade before other market participants become aware of the news—and it's a race that is won and lost in milliseconds.

CNBC reported on a server farm situated on Washington's K Street lobbying corridor that markets itself as a co-location hub for firms looking to transmit Washington economic data at near light speed to New Jersey for trading. That building is connected to New Jersey-based trading computers via a superfast microwave transmission service.

(Read More: Wall Street's hottest address? K Street)

The data vendors market services such as "Alpha Flash" and "Event Driven Analytics" to help traders directly plug the electronic data into their algorithmic programs to execute trades.

NAR said its early sale of the data generates relatively little revenue itself. "The revenue we receive is only a bare fraction of the production costs," Molony said in an email. "We supply the data for the public good, but have a big net loss if viewing purely in financial terms. Also, the agreement with one of the data vendors is essentially a trade. We provide them our data in exchange for access to their services."

Separately, NAR also maintains a so-called "lock up room" in which members of the media are given the data 30 minutes in advance and not permitted to release it from their computers until 10 a.m. sharp. A member of the NAR staff issues a verbal countdown for those reporters, saying, "3, 2, 1, Go."

Molony said that the race to be first has gotten so intense that even that simple command is being parsed. He said he had a conversation with a media organization bureau chief who asked exactly when during the word "go" his reporters were allowed to hit their send buttons.

"Does that mean we can hit the switch at the 'gh', or do we have to wait for the 'oh?'" the bureau chief asked.

—By CNBC's Eamon Javers. Follow him on Twitter: . Stephanie Dhue contributed to this article.