Nothing is guaranteed. There are absolutely down years (and down decades) where negative returns are possible. "There's no skill or activity involved" is a gro

Nothing is guaranteed. There are absolutely down years (and down decades) where negative returns are possible. "There's no skill or activity involved" is a gross simplification. When you save funds in a lower-risk security like bonds, you're being paid interest in exchange for the time-value of not using that money. The value-producing activity here is letting somebody else use your money instead of yourself. When you invest in higher-risk securities (like the stock market), it's the same but with an added premium in exchange for the risk. The more risk you take on, the higher the return. Make no mistake, the risk is very real. But if you properly diversify and work over a long enough time horizon (again, the implication here is that you might not be able to access your money without loss for a decade+ in a large downturn), it's possible to constrain that risk to within an acceptable envelope.