KX is a privately owned software company that sells a time series database kdb+, used for financial modeling and data analysis, and its associated proprietary programming language q.

In 2014, First Derivatives increased their ownership interest to 65 percent; in 2018, the company (now FD Technologies plc) announced plans to buy out the remaining shares of KX.

[9] KX has offices in New York City, London, England, Ireland, Germany, Australia, Singapore, Tokyo, and Hong Kong.

[12] Initially, Kx Systems had an exclusive contract with Swiss global financial services firm UBS to provide them with the K language.

[19] In July 2018, FD Technologies bought all remaining shares in KX Systems that it did not already hold;[20] Whitney and Lustgarten then went on to found Shakti.