Canadian investors have until mid-day on December 24th to book capital gains and losses for the year. As there is a three-day settlement period for stock trades and since December 25 and 26 are statutory holidays in Ontario, the trades will settle in the 2015 calendar year.
If you are selling US equities, the deadline is December 26th.
This is one of those tax rules where the CRA and IRS differ – the IRS will consider a disposition on the 31st of December to be valid for the 2014 calendar year.
There is some element of psychology that goes on in December – fund managers will not want to be seen (embarrassed) with certain holdings on their year-end statements, and investors have some tax incentive to ensuring that they book losses before year end to offset income taxes. This creates supply pressure on a reasonable number of stocks that experience declines throughout the year. Clearly the theme in 2014 will be the declines experienced in oil and gas producers.