(Adds detail, background) AMSTERDAM, June 15 (Reuters) - The European Union has excluded some of the biggest investment banks with past involvement in breaches of antitrust rules from syndicated debt sales backing its up to 800 billion euro ($969 billion) COVID-19 recovery fund, the EU executive said on Tuesday. “The Commission will be undertaking a careful assessment of whether the primary dealers found guilty of breaching anti-trust rules have taken necessary remedial measures to terminate these practices and are ready to undertake to take steps to avoid their recurrence,” the European Commission said in a statement to Reuters. “Pending the completion of this assessment, these institutions will be admitted to the primary dealer network but will not be invited to tender for individual syndicated transactions,” it added. The Commission did not specify which banks were excluded, but a spokesperson for the Commission pointed to three cartel cases over the last three years which involved 10 of the bloc’s biggest primary dealer banks. It fined banks including Bank of America, Credit Agricole, Natixis, Nomura, Natwest Markets (formerly RBS) and UniCredit for breaching antitrust rules by participating in bond cartels in two separate cases in April and May this year. Deutsche Bank also participated in one of the cartels but was not fined as it revealed the cartel to the Commission. Barclays, Citigroup, JPMorgan and Natwest were fined in 2019 for rigging the foreign exchange market. Those banks are among the EU’s 39 primary dealers, which manage syndicated debt sales for the bloc -- where they sell the debt directly onto end investors -- for lucrative fees. This helps motivate them to participate in less lucrative debt auctions, which the EU will start from September. Spokespeople for Nomura, BofA, Barclays, Natixis, Credit Agricole, NatWest, Deutsche Bank, UniCredit, Citi and JP Morgan all declined to comment. The spokesperson said the banks “at some point” would rejoin the syndications. The Financial Times reported the news on Tuesday following a report by Refinitiv’s capital markets news service IFR on Friday. The European Union on Tuesday raised 20 billion euros ($24.25 billion) from the first bond backing its recovery fund on the back of near-record demand. That deal was led by joint lead managers BNP Paribas, DZ Bank, HSBC, IMI-Intesa Sanpaolo and Morgan Stanley, while Danske Bank and Santander are co-lead managers. ($1 = 0.8253 euros) Reporting by Yoruk Bachceli and Dhara Ranasinghe; Editing by Rachel Armstrong and Emelia Sithole-Matarise Our Standards: The Thomson Reuters Trust Principles.