I just learned about this so want to share. If you're like me, you've likely had a large pension adjustment (PA) applied by the CRA every year only leaving you like $3-5k of RRSP room. The PA is calculated on your T4 each year and applied to the next years RRSP room. This is significant for us because our severance must be paid out in a lump sum and so there's no option to taking severance over multiple tax years to drop into lower tax brackets. The PA always bothered me because I thought 'what if we don't actually get our pension in the end because of bankruptcy/buyout/whatever' (eg: Sears).
So I just learned the way this is dealt with the pension plan issues a form T10 - Pension Adjustment Reversal (PAR) within 60 days of turning over the commuted value. According to ChatGPT it works like this... The Pension plan calculates all the pension adjustment you've had in the history of the company and adds them up, then subtracts the commuted value (CV). The difference is your PAR and it will be available in the next tax year as extra RRSP room and show up on your notice of assessment.
Example:
You are laid off in December 2025. You take your Pension CV of $200k in 2025 which becomes a tax sheltered LIRA. Over 15 years with the company you've lost $300k in RRSP room through PA's ($20k/yr * 15). Your PAR = $300k - $200k = $100k. By Feb 2026 the pension plan must report the $100k PAR to CRA. In spring 2026, your Notice of Assessment will show you have a $100k PAR, basically $100k extra RRSP room in 2026. Then also in 2026 you take your deferred severance of $200k and you can buy $100k of RRSPs that year, tax sheltering half of your severance.