Effective post-mortem planning requires careful modelling of alternative strategies to achieve the most tax-efficient outcome. The simplified scenario below illustrates how a post-mortem pipeline and a subsection 164(6) loss carryback can mitigate the double taxation that typically arises on death.

The Scenario

David, a long-time owner-manager and resident of Ontario, died in 2025 owning all the shares of a private corporation (“Davidco”).

At the time of death:

• Fair market value (FMV): $5,000,000 
• Adjusted cost base (ACB): $500,000
• Paid-up capital (PUC): $500,000 

Pursuant to subsection 70(5) of the Income Tax Act (ITA), David is deemed to have disposed of his shares at FMV immediately before death, resulting in a capital gain of $4,500,000.

Absent post-mortem planning, two layers of tax arise:

1. Capital gains tax on the deemed disposition: $1,204,425 
2. Dividend tax on the extraction of corporate surplus: $2,387,000 

As a result, David’s $5 million estate is reduced to $1,408,575, representing an effective tax rate of 71.83%. With appropriate planning, this outcome can often be reduced to a single level of tax.

Tax planning strategies

Two commonly used post-mortem planning strategies are outlined below. 

Post-mortem pipeline

Under a pipeline strategy, the estate transfers the shares of Davidco to a newly incorporated corporation (“Newco”) in exchange for a promissory note equal to the FMV of the shares. The note is repaid over time, and Davidco and Newco are subsequently amalgamated.

This approach converts what would otherwise be a taxable dividend into a tax-free repayment of capital. In this scenario, the pipeline strategy yields after-tax proceeds of $3,795,575, representing an effective tax rate of 24.09%.

Subsection 164(6) loss carryback

Alternatively, the estate may implement a loss carryback strategy under subsection 164(6). The Davidco shares are redeemed, triggering a capital loss in the estate, which is carried back to offset the capital gain reported on David’s terminal return.

This strategy results in after-tax proceeds of $2,851,700 and an effective tax rate of 42.97%.

Illustrative tax impact

How the strategies work

Post-mortem pipeline

A pipeline strategy mitigates double taxation by converting a corporate distribution into a tax-free repayment of a bona fide debt. To be effective, the structure must be carefully implemented, with particular attention to timing, documentation, and the continuity of the underlying business.

When properly executed, a pipeline can eliminate—rather than merely defer—the second layer of tax. 

Subsection 164(6) loss carryback

The subsection 164(6) strategy mitigates double taxation by triggering a capital loss in the estate, typically through a share redemption. This loss is carried back to offset the capital gain reported on the deceased’s terminal return.

Provided the transaction is completed in accordance with all statutory requirements, the loss carryback can effectively eliminate the initial capital gains tax.

Additional planning considerations

Hybrid sequencing 

In certain circumstances, a hybrid approach may be appropriate. For example, the estate may first implement a subsection 164(6) loss carryback to eliminate the terminal capital gain and subsequently undertake a pipeline reorganization to extract any remaining corporate surplus. This sequencing can enhance flexibility while optimizing overall tax outcomes.

Refundable tax balances

Where the corporation has refundable tax attributes—such as refundable dividend tax on hand (RDTOH) or assets with accrued gains—the subsection 164(6) strategy may produce a more favourable outcome than illustrated. These attributes should be carefully modelled when evaluating alternatives.

Final considerations

Selecting the optimal post-mortem planning strategy depends on several factors, including:

• The estate’s liquidity requirements 
• Ongoing business objectives 
• Timing of distributions to beneficiaries 
• Administrative complexity and compliance considerations 
• Corporate tax attributes

To preserve flexibility, wills, shareholder agreements, and trust deeds should explicitly permit the implementation of post-mortem reorganizations.

Key takeaways

• Double taxation on death can be significant

Private company shares may be subject to both capital gains tax on death and dividend tax on extraction, materially reducing estate value. 

• Post-mortem planning can reduce tax to a single layer

Properly structured strategies can eliminate or significantly mitigate the second level of tax. 

• Pipeline planning is often the most tax-efficient

A pipeline can convert taxable dividends into tax-free repayments of capital, typically producing the lowest overall tax cost when properly implemented. 

• Subsection 164(6) provides a practical alternative

A loss carryback can offset the terminal capital gain and may be preferable where corporate tax attributes enhance outcomes. 

• Timing and execution are critical

Both strategies are highly technical and subject to strict legislative and administrative requirements. 

• Hybrid approaches may enhance outcomes

Combining strategies can improve flexibility and optimize tax efficiency in appropriate circumstances. 

• Corporate attributes can materially impact results

Refundable tax balances and unrealized gains should be carefully considered when modelling alternatives. 

• Planning must be supported by legal documentation

Estate and corporate documents should provide sufficient flexibility to implement post-mortem strategies. 

• Early planning is essential

Proactive structuring during lifetime ensures that planning opportunities remain available and can be executed efficiently.