Not only did the synergies fail to materialize, but separate management strategies and work habits simply never came together.

FORBES: American + U.S. Airways: A match made in heaven?

Based on the CBO sensitivity analysis above, that means that about 40 percent of the projected deficit reduction will fail to materialize.

FORBES: A Laffer Curve Warning about the Economy and Tax Revenue for President Obama and other Class Warriors

Best Buy and Dell, two ailing companies that are targets of potential founder-led leveraged buyouts, are up better than 30% apiece, gains that could unravel if deals fail to materialize.

FORBES: With Apple Absent, Market Starts 2013 With A Big January