There is additional significance respecting the effective dates of dividends for 2017

For 2017, there may be additional significance as to whether a dividend was paid in that year or 2018 given that 2017 was the last year that dividends could be "sprinkled" freely to adult family members, and given that the U.S. "Transitional Tax" on most accumulated earnings and profits may cause Americans to wish dividends to be considered to have been paid to them in 2017 by their Canadian companies in order to generate Canadian tax to offset the Transitional Tax.

CRA recognizes that a transaction may be "papered" after the fact, but backdating is improper where it is tantamount to a retroactive characterization or alteration of reality.

The authors recommend:

an express CRA policy permitting the crystallization of compensation and dividends in an owner-managed business to occur, for example, up to 60 days after fiscal year end (to match the due date for T5 slip filing). This administrative concession would codify the CRA's existing practice.

They also note that a formulaic approach to drafting resolutions before year end respecting the determination of the salary/loan repayment/dividend mix may be legally effective.

Neal Armstrong. Summary of Kevyn Nightingale and John Sorensen, "Backdating of Dividends," Tax Topics (Wolters Kluwer), No. 2392, January 11, 2018, p. 1 under General Concepts – Effective Date.