'To whom it may concern' : I've always thought that it referred to this current writing
(directed at the party whom this writing may concern). Am I right?
If so, then technically, does it lack an antecedent? Why not specify the real noun?
For example: 'to whom this cablegram/facsimilie/letter/memorandum... may concern' ?
Whatever follows your colon is the "antecedent." (Though in this case I guess it's a "subsequent."
Consider this sentence:
It's not clear to me what you contribute to this company.
'It' here clearly refers to 'what you contribute to this company." By the same token:
To whom it may concern: I demand the immediate return of my red Swingline stapler.
In this sentence, "it" refers--if not in a strict grammatical sense, then in a semantic sense--to the loss of the stapler and the need for its return.
As already noted in the comments, however, in practice it's simply a set phrase, with no need for a formal antecedent.
To whom it may concern" is a letter salutation used in business correspondence. The pronoun "it" is commonly known that its antecedent is this correspondence (cablegram, facsimile, letter, or memorandum) on which this salutation) appears. We can use "it" to refer to an unspecified or implied antecedent (The Free Dictionary).
