Citigroup Inc. announced today that it has made a minority investment in the BATS ECN, a fast-growing market center offering trading in U.S. equity securities. Financial terms of the investment were not disclosed.

Citi participated in the latest BATS investment round along with several existing BATS investors, totaling US$45 million in new funding for BATS.

BATS Trading Inc. was founded in June 2005 in response to rapid consolidation in the exchange space. It is designed to handle high-speed, high-volume, anonymous, reliable, algorithmic trading. Other investors in BATS include Credit Suisse, Getco LLC, Lehman Brothers, Lime Brokerage LLC, Merrill Lynch, Morgan Stanley and Wedbush Inc.

“We are pleased to invest in BATS Trading, which complements our in-house electronic execution capabilities as well as our ongoing strategic and financial investments in this space,” said James Pak, head of market structure investments at Citi, in a release.

“We are proud to announce Citi’s investment in BATS, a move which further validates our aggressive, dealer-friendly business model,” said BATS chief executive Dave Cummings. “BATS was built to serve the dealer community and we thank all of our partners and subscribers for their continued support.”