Many 401(k) plans allow taxpayers to make Roth contributions as long as the plan has a designated Roth account. Your plan may also allow you to transfer amounts to the designated Roth account in the plan or borrow money.  ...

Are you wondering if there's a hard and fast rule about what income is taxable and what income is not? The quick answer is that all income is taxable unless the law specifically excludes it. But as you might have...