(Bloomberg) -- Nasdaq and the New York Stock Exchange were dealt a blow in their bids to block the Securities and Exchange Commission from implementing new rules for stock-trading data. 

A decision by the US Court of Appeals for the District of Columbia Circuit on Tuesday not to review regulations the SEC passed in December 2020 allows the agency to move ahead with a push to make trading data more readily available. The changes could negatively impact exchange operators’ lucrative market-data businesses. 

The SEC and Nasdaq declined to comment. NYSE didn’t respond to a request.

The court ruling is the latest twist in the years-long battle over exchanges’ data streams, which include information on market dynamics and certain types of transactions. The SEC unanimously passed the new regulations to push more of that information into so-called public data feeds, which are lower cost and more standardized. 

Stock exchange operators opposing the rules have argued they will result in greater information asymmetries and make the market more prone to disruptions. Meanwhile, the overhaul, which was a key part of the SEC’s effort to crack down on stock-market data during the Trump administration, has support from brokerages that say the platforms too much power over the information streams that are a lifeblood of modern trading.

The court’s decision may mean that “new players can enter the market, create competition, and potentially the price of market data will go down,” Bloomberg Intelligence analyst Larry Tabb said. “But prices could also go up, given there is nothing about what price the exchanges have to sell the data for,” he said.

The regulation could reduce exchanges’ net data revenue by 8%, according to Bloomberg Intelligence calculations.

Bloomberg LP, the parent company of Bloomberg News, is among firms that in the past have contested exchanges’ fee increases for private data feeds.

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