Interesting. Thanks for pointing that out.
> For accounting purposes, a firm is allowed to define a "quarter" as either a span of 3 months or else a span of 13 weeks. A "year" is then four quarters. ... Consequently, a firm that defines its quarters in terms of weeks needs to hold a 14-week quarter every four or five years. [1]
[1] http://www.slate.com/blogs/moneybox/2014/02/06/_14_week_quar...