MDDL, the Market Data Definition Language, is an XML-based messaging format for exchanging information related to
- Financial Instruments
- Corporate events related to the financial instruments
- Market-related data
MDDL was developed by FISD (Financial Information Services Division) of SIIA (Software & Information Industry Association). The initiative for the use of XML in market data exchange was started in the year 2000 and has been gaining industry-wide acceptance.