How ESPPs are taxed in Canada

An Employee Stock Purchase Plan lets you buy company shares at a discount, often 5–15%, sometimes off the lower of two prices. That discount is a taxable employment benefit in the year you purchase — it’s treated as extra pay, generally appearing on your T4, and taxed at your marginal rate.

Here’s the part people get wrong. Because you were already taxed on the discount as income, your adjusted cost base is the full fair market value at purchase — not the discounted price you actually paid. The tax you paid on the benefit “buys up” your cost base to market.

When you sell, the difference between your proceeds and that full-market-value cost base is a capital gain or loss — only the taxable portion is included. Sell immediately at purchase and the gain is near zero (you already paid income tax on the benefit). Hold, and any further movement is a normal capital gain.

ESPPs buy shares each period at different prices, and those lots pool with any other identical shares you own into one average cost base. Across a few years of contributions plus shares from other sources, tracking the correct pooled ACB by hand gets messy fast.