Does a non-profit organization have to pay tax on its investment income the way a charity doesn't?

This is one of the more genuinely tricky corners of NPO taxation, and the honest answer is: it depends. An NPO's general tax exemption is not unlimited the way a registered charity's is for its investment income. A registered charity generally doesn't pay tax on income earned from its investments, but an NPO's exemption can work differently — in some circumstances, investment or property income an NPO earns can actually be taxable, even though the same organization's income connected to its core exempt purpose is not.

Whether that applies to a specific NPO depends heavily on its particular purposes and activities — how the investment income relates to what the organization actually does, and whether the organization is operating consistently with a genuine non-profit purpose rather than functioning more like a taxable enterprise that happens to be structured as an NPO. There's no flat yes-or-no rule that applies to every NPO equally, which is exactly what makes this area easy to get wrong.

Any NPO holding significant investments, or generating meaningful income from them, should get that specific fact pattern reviewed rather than assuming its investment income is automatically as tax-free as a charity's would be.