By Rob Cox
The author is a Breakingviews columnist. The opinions expressed are his own.
Nine years ago, Breakingviews proposed an “extreme idea” to Citigroup’s then-leader Charles Prince. The $240 billion New York bank’s market capitalization was lower than the worth of its parts valued separately. By splitting into three separate units, the idea was, Prince could hand shareholders an extra $50 billion or so, the equivalent of one entire U.S. Bancorp at the time.