Hi vonAnden,
take a look at this answer here http://answers.splunk.com/answers/129424/how-to-compare-fields-over-multiple-sourcetypes-without-join-append-or-use-of-subsearches.html to get an idea how it could be done.
Based on your two searches, I would start off by using the two types and eval all needed fields and stats them.
Type=trade-bought OR Type=trade-confirmed | ....
Hope this helps ...
cheers, MuS
btw: a subsearch expands to a list of result=foo OR result=boo OR result.... and looking at your used search this makes no sense, because this will be used in an eval ....
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