Complex sentence: Its name is derived from former anchor tenant, Pacific Western Bank of Oregon, owned by PacWest Bancorp, when PacWest's Oregon operations were acquired by KeyCorp in 1986, it became part of KeyBank.
Split into simpler sentences: Its name is derived from former anchor tenant, Pacific Western Bank of Oregon, owned by PacWest Bancorp. However, PacWest's Oregon operations were acquired by KeyCorp in 1986 and became part of KeyBank.