Since he won't release his tax returns, and does admit they'd be politically damaging, all we can do is guess.
This is one in a series of speculative diaries wondering what could possibly be worth the price he is paying by remaining secretive.
Today's idea: nothing in particular. He's just that secretive. The Olympic records were purged; Bain Capital is notoriously closed mouthed; his minions bought their hard drives from the state of Massachusetts so there would be no record left behind.
Why Willard M. Romney feels compelled to be so secretive is a matter for amateur psychoanalysis. Perhaps he always tries to see how much he can get away with and takes things right up to the legal limit. Perhaps he has deep seated feelings of inadequacy. Perhaps he assumes he has enemies who are out to get him and he must hide from these enemies. Maybe a combination of the above.
But the pattern is there. Romney is a super-secretive person, and that is probably not a trait we want in a President (think: Richard Nixon).
Other diaries in the series.
Hiding stuff from Ann Romney
Rich people write-offs
Olympics corruptions
Medical expenses
Political contributions
Foreign investments
Church contributions exceed taxes