For raw performance needs, many financial services schema were going to be denormalized anyway. Compression was a great way to claw some of the resulting inefficient storage back.
My recollection was that DB2 did not support multi version concurrency control like Oracle and Postgres did. The result was a lot of lock contention with DB2 if you were not careful. MVCC was eventually added to DB2, but by then it was too late.
Nobody got fired for buying IBM^W NoSQL