Do I only have to pay income tax on capital gains?
On the revenue only. This amount of 10$ will be considered as interest and fully taxable. It will not be a capital gain. But why would you decide to declare it as an income? 100$ is insignificant. If you lend small amount to friends it cannot be considered a lending business.
In the US, dividends have special tax treatment similar to, but not the same as Capital Gains. No easy way to transform one to the other, the very fact that you invested your money in a company that has returned part of your capital as income means it is just that, income. Also in the US, you could invest in Master Limited Partnerships. These are companies that make distributions that are treated as a return of capital, instead of dividends. Throughout the life of the investment you receive tax forms that assign part of the operating expense/loss of the company to you as a tax payer. Then at the end of the investment life you are required to recapture those losses as Capital Gains on sale of the stock. In some ways, these investments do exactly what you are asking about. They transform periodic income into later capital gains, basically deferring tax on the income until the sale of the security. Here is an article I found about MLPs coming to the UK through an ETF: Master Limited Partnerships in the UK I think you're misunderstanding how tax brackets work. If you make $1 more and that bumps you into a higher bracket, only THAT particular dollar will be taxed at the higher tax bracket rate... Not your entire income.  Short term capital gains are treated as income.  Long term capital gains have a special tax rate currently. In response to your points #1 and #2: In general, yes it is true that capital gains are only subject to half one's marginal rate of income tax.  That doesn't mean 50% of the gain is due as tax... rather, it means that if one's marginal tax rate (tax bracket) on the next $10K would have been, say, 32%, then one is taxed on the gain at 16%.  (The percentages are examples, not factual.) However, because these are employee stock options, the tax treatment is different than for a capital gain!    Details: On the Federal tax return are lines for reporting Security option benefits (Line 101) and Security options deductions (Line 249).  The distinction between a regular capital gain and an employee stock option benefits is important.  In many cases the net effect may be the same as a capital gain, but the income is characterized differently and there are cases where it matters.  Somebody who is about to or has realized employee stock option benefits should seek professional tax advice. In response to your next two points: No, one cannot transfer a capital gain or other investment income into a TFSA immediately after-the-fact in order to receive the tax-free benefits of the TFSA on that income.  Only income and gains earned within a TFSA are free from tax – i.e. The options would have to have been in the TFSA before being exercised.  Once a gain or other investment income has been realized in a non-sheltered account, it is considered taxable.  The horse has already left the barn, so to speak! However, despite the above, there is another strategy available:  One can create an offsetting deduction by contributing some of the realized gain into an RRSP.  The RRSP contribution, assuming room is available, would yield a tax deduction to offset some tax due on the gain.  However, the RRSP only defers income tax; upon withdrawal of funds, ordinary income tax is due (hopefully, at a lower marginal rate in retirement.) There is no minimum amount of time that money or assets have to be inside a TFSA to benefit from the tax-free nature of the account.  However, there are limits on how much money you can move into a TFSA in any given year, and many folks weren't aware of the rules. p.s. Let me add once more that this is a case where I suggest seeking professional tax advice. To try to answer the three explicit questions: Every share of stock is treated proportionately: each share is assigned the same dollar amount of investment (1/176th part of the contribution in the example), and has the same discount amount (15% of $20 or $25, depending on when you sell, usually). So if you immediately sell 120 shares at $25, you have taxable income on the gain for those shares (120*($25-$17)). Either selling immediately or holding for the long term period (12-18 mo) can be advantageous, just in different ways.   Selling immediately avoids a risk of a decline in the price of the stock, and allows you to invest elsewhere and earn income on the proceeds for the next 12-18 months that you would not otherwise have had.  The downside is that all of your gain ($25-$17 per share) is taxed as ordinary income.   Holding for the full period is advantageous in that only the discount (15% of $20 or $25) will be taxed as ordinary income and the rest of the gain (sell price minus $20 or $25) will be taxed at long-term capital gain tax rates, which generally are lower than ordinary rates (all taxes are due in the year you do sell).  The catch is you will sell at different price, higher or lower, and thus have a risk of loss (or gain). You will never be (Federally) double taxed in any scenario.  The $3000 you put in will not be taxed after all is sold, as it is a return of your capital investment.  All money you receive in excess of the $3000 will be taxed, in all scenarios, just potentially at different rates, ordinary or capital gain.  (All this ignores AMT considerations, which you likely are not subject to.) As JoeTaxpayer illustrated, yes you can.  However, one thing to remember is that unless you live in a state with no state income tax, there may be state tax to pay on those gains.  Even so, it's likely a good idea if you expect either your income (or the federal capital gains tax rate) to rise in the future. Sorry, no, any time you sell for a profit you owe tax. "IRS Pub 554 states (click to read full IRS doc):  ""Do not file a federal income tax return if you do not meet the filing requirements and are not due a refund. ... If you are a U.S. citizen or resident alien, you must file a return if your gross income for the year was at least the amount shown on the appropriate line in Table 1-1 below. "" You may not have wage income, but you will probably have interest, dividend, capital gains, or proceeds from sale of a house (and there is a special note that you must file in this case, even if you enjoy the exclusion for primary residence)" Note the above is only for shares. There are different rules for other assets like House, Jewellery, Mutual Funds, Debt Funds. Refer to the Income Tax guide for more details.