According to a draft EU document, stock exchanges throughout the European Union will be forced to pass over data on market transactions on a single "tape" allowing investors to spot the best deals and help the bloc compete better with London following Brexit.
The plan is part of a slew of measures from the EU's executive European Commission due next week in an effort to improve capital markets following the UK's exit from the bloc last year.
A so-called "consolidated tape," a record of trading prices that is a feature of Wall Street, has long been an ambition of banks and asset managers who face a plethora of venues that trade the same securities.
Exchanges, however, have resisted turning over the data for an affordable fee.
Exchanges would be required to contribute to a tape for stocks and bonds in exchange for "appropriate remuneration," according to the document.
According to the document, "all market data suppliers would have to make standardised core market data available to market data aggregators."
The proposal said that exchanges would be guaranteed a "minimum revenue" in exchange for providing pricing data.