CRA accepts that a price adjustment clause can operate re statute-barred transactions to affect a tax attribute that is used in the current year

CRA accepts that where a price-adjustment clause retroactively adjusts a tax attribute, such as adjusted cost base, that arose from a rollover transaction that occurred in what is now a statute-barred year, that adjustment may occur “for a taxation year that is otherwise not statute-barred if it has an impact on the tax consequences for that year.”

Neal Armstrong. Summary of 5 October 2018 APFF Roundtable, Q.15 under s. 152(4).