[AaronBrown]

This is an important effect in business planning. One of the major reasons for a company diversifying is to save on taxes by guaranteeing all losses can be used. While losses can be carried forward to future tax years (and back in some cases) there are limitations to this and you lose the present value of the cash flows.

Similarly, individuals generally structure portfolios to have a high probability of making money every year. You can do that by diversifying, or by making sure you generate enough income from safe investments to offset any losses from risky ones.