Flow-Through Shares Explained: How They Work and What They Cost

How Canadian flow-through shares pass exploration deductions to investors, where the METC stands in 2026, and the after-tax math on $10,000.

Key takeaways

Flow-through share investors can deduct 100% of the amount invested as renounced Canadian exploration expense, spread by when expenses are renounced.
The 15% Mineral Exploration Tax Credit covers flow-through agreements entered into after March 2025 and before April 2027, under Bill C-15.
In a top-bracket BC example, $10,000 of METC flow-through shares has an after-tax cost of $3,952.50 and a zero cost base.

A flow-through share lets a Canadian exploration company pass its exploration spending to the investor as a tax deduction. The federal Mineral Exploration Tax Credit adds 15% on top for eligible grassroots work, and that credit is now law through agreements signed before April 2027. The tax breaks are real, and so is the price: investors usually pay more than the regular share price and end up with a cost base of zero.

How the structure works

A flow-through share is a new share issued by a principal-business corporation under a written flow-through share agreement. The company spends the money on Canadian exploration expense (CEE), such as drilling and surveys to find a mineral deposit in Canada, and then renounces those expenses to the investor. The CRA treats renounced expenses as if the investor incurred them.

The investor can deduct 100% of the amount invested, spread according to when the expenses are renounced. PDAC, the exploration industry association, says flow-through financing accounts for about 70% of the money raised on Canadian exchanges for exploration.

The company side has its own rules:

The look-back rule. A company can renounce expenses it will incur in the following calendar year with an effective date of December 31 of the year the money was raised. Investors get the deduction a year early.
Part XII.6 tax. A company using the look-back rule owes Part XII.6 tax on renounced amounts it has not yet spent, which gives it a reason to spend on schedule.
Shortfalls. If the company does not spend the money on eligible CEE, it has to reduce what it renounced, and the investor loses that part of the deduction.

The Mineral Exploration Tax Credit in 2026

The METC is a 15% non-refundable federal credit on eligible flow-through mining expenditures. It had been scheduled to expire on March 31, 2025. Budget 2025, tabled November 4, 2025, confirmed a two-year extension, and Bill C-15, the Budget 2025 Implementation Act, received Royal Assent on March 26, 2026.

The Library of Parliament summary of Bill C-15 describes the extended window as eligible expenses incurred after March 2025 and before 2028, renounced under flow-through share agreements entered into after March 2025 and before April 2027.

The same bill expanded the 30% Critical Mineral Exploration Tax Credit (CMETC) to 12 more minerals: bismuth, cesium, chromium, fluorspar, germanium, indium, manganese, molybdenum, niobium, tantalum, tin and tungsten. That applies to agreements signed after November 4, 2025 and on or before March 31, 2027. The same dollar of spending can earn the METC or the CMETC, not both.

Unused credits can be carried back three years and forward 20 years, according to PDAC.

The costs investors take on

Zero cost base. Once the deductions are claimed, the adjusted cost base of the shares drops to $0. Every dollar received on sale is a capital gain.
The credit comes back as income. METC and CMETC amounts reduce the investor’s cumulative CEE pool. A negative pool balance at year end is taxable income, so a credit claimed after the pool is fully deducted gets taxed back.
Alternative minimum tax. Miller Thomson notes that for AMT purposes the flow-through deduction is limited to specified resource income, which most individuals do not have. Large purchases can trigger AMT.
The premium. Flow-through shares are usually priced above the company’s regular shares. The investor pays extra for the tax attributes.
Illiquidity and risk. These are exploration companies, and private placement shares generally come with resale restrictions.

The math: $10,000 into flow-through shares

Assumptions: a British Columbia resident taxed at the 2026 top combined federal and provincial rate of 53.50% (taxable income over $265,545). The capital gains rate at that level is 26.75%, based on a 50% inclusion rate. All spending qualifies for the 15% METC. Provincial flow-through credits are left out for simplicity.

Step	METC (15%)	CMETC (30%)
Amount invested	$10,000.00	$10,000.00
Tax saved by CEE deduction (10,000 x 53.50%)	$5,350.00	$5,350.00
Federal credit	$1,500.00	$3,000.00
Tax on credit clawed back through CEE pool (credit x 53.50%)	minus $802.50	minus $1,605.00
Net tax benefit	$6,047.50	$6,745.00
After-tax cost of the shares	$3,952.50	$3,255.00

Now the sale. With a $0 cost base, selling the METC shares for the full $10,000 means capital gains tax of $2,675 (10,000 x 26.75%), leaving $7,325 after tax.

The after-tax break-even is the sale price where proceeds after capital gains tax equal the $3,952.50 after-tax cost: 3,952.50 divided by 0.7325, or about $5,396. On these assumptions, the shares can be sold for about 46% less than the investor paid before the position loses money after tax.

Add the premium. Suppose, as an illustration, the regular shares trade at $1.00 and the flow-through shares are priced at $1.20, a 20% premium. $10,000 buys 8,333 shares with a market value of $8,333 on day one. The break-even of $5,396 works out to about $0.65 a share, or 35% below the regular share price at the time of the financing. The premium eats part of the tax cushion before the stock moves at all.

At a lower tax rate, every line shrinks. The structure is worth the most to investors in the top bracket.

Premiums, discounts and charity structures

The company gets a higher price per share than it could get for regular shares, which means less dilution for the same amount of exploration money. The investor accepts the premium because the tax savings are larger than the extra cost, at least at high marginal rates.

Some offerings go further. In a charity flow-through, the investor buys the shares, claims the deductions, and immediately donates the shares to a charity. A liquidity provider then buys the shares from the charity. Miller Thomson describes structures where the investor gets both a donation credit and the original flow-through deductions. The combined tax value is what lets these deals carry larger premiums than a plain flow-through offering.

What to watch

March 31, 2027: the last date to sign a flow-through share agreement that qualifies for the METC or the expanded CMETC under current law.
The next federal budget for any further METC extension.
Flow-through financings announced in November and December, and whether their agreements are signed before the March 31, 2027 cut-off.
CRA guidance and Form T1229 updates for the 2026 tax year.
Company disclosures on how flow-through proceeds were spent, including any renunciation shortfall.

Sources

Frequently asked questions

How do flow-through shares work in Canada?

A flow-through share is a new share issued by a principal-business corporation under a written flow-through share agreement. The company spends the money on Canadian exploration expense, such as drilling and surveys, then renounces those expenses to the investor. The CRA treats them as if the investor incurred them, so the investor can deduct 100% of the amount invested.

Is the Mineral Exploration Tax Credit extended in 2026?

Yes. Budget 2025 confirmed a two-year extension of the 15% METC, and Bill C-15 received Royal Assent on March 26, 2026. The extended credit applies to eligible expenses incurred after March 2025 and before 2028, renounced under flow-through share agreements entered into after March 2025 and before April 2027.

What are the downsides of flow-through shares?

Once deductions are claimed, the shares’ adjusted cost base drops to zero, so every dollar received on sale is a capital gain. Credits reduce the investor’s CEE pool and can be taxed back. Large purchases can trigger alternative minimum tax. Flow-through shares are usually priced above regular shares, and private placement shares generally carry resale restrictions.