Fidelity Investments recent reported that the average 401(k) balance rose 15.5% last year to $89,300. But as it turns out, many investors have hidden assets that will make or break their financial prospects in retirement.

In the following video, Dan Caplinger, The Motley Fool's director of investment planning, looks at this hidden asset and its implications for retirees. He notes that the Fidelity study looked at people who have both 401(k) accounts and IRAs, and found that the average total retirement assets among those workers was $261,400. Dan explains the sources of those IRA assets and points out how vital it is to consider all of your financial resources when considering what your financial plan for your retirement years should be.

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Dan Caplinger and the Motley Fool have no position in any stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.