At $31 billion, GE's pension shortfall is the biggest among S&P 500 companies and 50 percent greater than any other corporation in the U.S. It's a deficit that has swelled in recent years as Immelt spent more than $45 billion on share buybacks to win over Wall Street and pacify activists like Nelson Peltz.

In the last two years, GE spent little more than $2 billion on total pension contributions, which hasn't been nearly enough to keep the overall shortfall from widening. (The company also curtailed capital investments.) At the end of last year, its pension had $94 billion in obligations but only $63 billion in assets — a funding ratio of 67 percent.

In addition to the "anemic" free cash flow from its industrial businesses, GE's pension hole and its indebtedness helped subtract roughly $8 a share from its equity value, based on a sum-of-the-parts analysis by Cowen & Co. That's equal to $70 billion in market capitalization.