SIX Digital Exchange (SDX) is a securities exchange firm based in Zurich, Switzerland that six digital exchange (sdx) is a finma-licensed financial market infrastructure for the issuance, trading, settlement and custody of digital assets, operating a distributed ledger based stock exchange and central securities depository. part of switzerland six group, it has issued over 2 billion swiss francs of digital securities for institutions including ubs, commerzbank and the world bank. in 2026 finma approved merging sdx into the six sis central securities depository, creating a combined post-trade environment for conventional securities and crypto assets. sdx is expanding to euro-denominated digital bonds. They serve clients in Switzerland. SIX Digital Exchange (SDX) is listed on The Token Playbook's vetted provider registry at thetokenplaybook.com/registry/six-digital-exchange-sdx.