WASHINGTON, Sept 27 (Reuters) - The Commodity Futures Trading Commission (CFTC) on Monday said Citigroup had agreed to pay $1 million to settle charges it violated swap data reporting rules and supervision rules, and breached a previous CFTC settlement agreed in 2017. That 2017 order found Citigroup"s broker-dealer failed to report certain swap data, among other lapses. The CFTC"s Monday order found that, subsequently, Citigroup continued fall down on its swap reporting. The CFTC said it had reduced the penalty to $1 million "in recognition of Citi"s substantial cooperation."