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Merger & takeover ACB calculator

Enter your position and deal terms to see your capital gain, tax-deferred rollover amount, and the new cost base on the acquirer's shares.

Your position in the acquired company
$
Deal terms
$
e.g. 0.5 = half a share per old share
$
At deal close date
$

How mergers and takeovers affect your ACB

When a company you own is acquired, the tax treatment depends entirely on the form of consideration you receive. The three scenarios are all-cash (full disposition), all-shares (section 85.1 rollover), and mixed cash-plus-shares (proportional allocation). Each has different reporting requirements.

For all-cash deals, the calculation is straightforward: your proceeds are the cash received, and your gain is proceeds minus ACB. For share-for-share exchanges, section 85.1 defers the tax entirely — your ACB transfers to the new shares with no immediate tax event.

Mixed deals are the most complex. The CRA requires you to allocate your original ACB proportionally based on the fair market values of the cash and share components at the deal close date. The cash portion triggers an immediate capital gain; the share portion rolls over tax-deferred.

How is ACB calculated after a merger in Canada?

It depends on the consideration. If you receive only cash, it is a simple disposition — your gain is cash minus ACB. If you receive only shares of the acquirer, section 85.1 provides a tax-deferred rollover where your old ACB transfers to the new shares. If you receive a mix of cash and shares, your ACB is allocated proportionally: the cash portion triggers a gain, and the share portion carries a prorated ACB forward.

What is a section 85.1 rollover?

Section 85.1 of the Income Tax Act allows a tax-free exchange of shares when a Canadian public corporation acquires shares of another Canadian public corporation by issuing its own shares. Your ACB transfers to the new shares with no immediate tax. The gain is deferred until you eventually sell the acquirer's shares.

Do I have a capital gain if I receive only shares in a takeover?

Not immediately, if it qualifies under section 85.1. Your gain is deferred — your original ACB is transferred to the new shares. However, this only applies to share-for-share exchanges of Canadian public corporations. Cross-border deals or private company acquisitions may have different rules.

How do I allocate ACB in a mixed cash and shares deal?

The formula is: New ACB = Old ACB x (FMV of shares received / Total FMV of all consideration). The gain on the cash portion equals Cash received minus (Old ACB x Cash FMV / Total FMV). This proportional allocation is required by the CRA.

What if I receive fractional shares in a merger?

Most acquirers pay cash-in-lieu of fractional shares. This cash-in-lieu is treated as a partial disposition: you calculate the gain on that fraction using the same allocation formula. The remaining whole shares carry the prorated ACB.

Related tools and guides

You might also need
Spin-off & split ACB calculator
For spin-offs that happen alongside mergers.
Adjusted cost base calculator
Track ongoing ACB of your new shares post-merger.
Capital gains calculator
Calculate the gain on the cash portion.
Not tax or legal advice. Always confirm capital gains reporting with a qualified accountant. · Made with love in Canada 🇨🇦
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