CME documentation states: "LMM – CME Designated Lead Market Makers are each allocated a configurable percentage of an aggressor order quantity before the remai

CME documentation states: "LMM – CME Designated Lead Market Makers are each allocated a configurable percentage of an aggressor order quantity before the remaining quantity passes to the next step." Certain matching algorithms allocate orders to LLM before considering FIFO - specifically algorithm T (LMM w/o Top). So I guess it depends on how strict is your definition of "FIFO order queue". https://cmegroupclientsite.atlassian.net/wiki/spaces/EPICSANDBOX/pages/46437544/CME+Globex+Matching+Algorithm+Steps https://cmegroupclientsite.atlassian.net/wiki/spaces/EPICSAN... https://cmegroupclientsite.atlassian.net/wiki/spaces/EPICSANDBOX/pages/46110273/Supported+Matching+Algorithms#SupportedMatchingAlgorithms-FIFOwithLMM https://cmegroupclientsite.atlassian.net/wiki/spaces/EPICSAN... (I don't know the internals of the mentioned exchanges)