Tradeweb, the over-the-counter multi-asset class online marketplace owned by Thomson Corp. and 10 brokerage firms, announced that Citi is acquiring a minority stake in the company, and will take a seat on its board.

Terms of the transaction were not disclosed. As part of this agreement, Citi will become a liquidity provider in a number of new Tradeweb markets, including interest rate swaps.

“Tradeweb’s reputation as a markets company is unmatched. As a liquidity provider, we have participated in the growing success of its online marketplaces. We are pleased to become even more involved with Tradeweb as an investor,” said Paco Ybarra, head of Fixed Income Currencies and Commodities Products at Citi.

“We are delighted to welcome Citi as an investor,” said Jim Toffey, CEO of Tradeweb. “Citi’s reputation as one of the world’s great trading firms speaks for itself. The liquidity they will bring to a number of new Tradeweb markets will be extremely beneficial to our clients.”

With the addition of Citi, the 10 dealers that are now invested in Tradeweb are: Credit Suisse, Deutsche Bank, Goldman Sachs, JPMorgan, Lehman Brothers, Merrill Lynch, Morgan Stanley, The Royal Bank of Scotland, and UBS.