Complex sentence: Penn Square Bank was a large commercial bank located in north Oklahoma City in the 50 Penn Place galleria complex, which made its name in high-risk energy loans during the late 1970s and early 1980's Oklahoma and Texas oil boom.
Split into simpler sentences: Penn Square Bank was a large commercial bank located in north Oklahoma City in the 50 Penn Place galleria complex. The bank made its name in high-risk energy loans during the late 1970s and early 1980s Oklahoma and Texas oil boom.