Waiting until the last minute to get your taxes done rarely makes sense. But this year, filing for an extension to file your taxes may be a really smart move -- even if you're ready to shoot your tax return to the IRS right now.


Sure, it may seem strange to ask for an extension if you already have your taxes done. But if you took advantage of the once-in-a-lifetime chance to convert an existing retirement account to a Roth IRA last year, then getting a tax extension gives you another six months to make some important decisions.

Roth IRAs, conversions, and extensions
In 2010, Congress opened the door to everyone to open a Roth IRA. Until then, income limitations had prevented high-income taxpayers from either contributing directly to a Roth account or converting an existing traditional IRA or 401(k) account to a Roth. But while the income limit on direct contributions remained, anyone was allowed to do a Roth conversion last year, regardless of income.

In addition, those who did Roth conversions last year got a one-time bonus: they could either choose to add the resulting taxable income from the conversion on their 2010 tax return or split it between their 2011 and 2012 returns. That provision gave tax-averse investors some comfort that they'd be able to plan for the additional tax liability that comes with Roth conversions. And now that relatively low tax rates appear to be locked in at least through 2012, you don't have to worry so much about a tax hike offsetting the benefit of getting to put off paying your taxes.

Investors have until their tax deadline this year to make that final choice about which year or years to include their conversion income. So without an extension, that would be next Monday. But by making a simple request to the IRS, you can have another six months before you need to decide.

Why wait?
Even if you're ready to get going with your return, having another six months before you lock in a final decision on your Roth conversion gives you some vital flexibility. In some circumstances, that flexibility will be vital.

The most important situation you could face is if you need to reverse your conversion. If your converted Roth has gone down in value, you can recharacterize the conversion and avoid any tax liability at all.

So on one hand, if you invested your newly converted Roth a year ago in shares of losing companies in an otherwise upward-trending market -- stocks like Johnson & Johnson (NYSE: JNJ) in health care, JPMorgan Chase (NYSE: JPM) and Wells Fargo (NYSE: WFC) among bank stocks, and Toyota Motor (NYSE: TM) in the auto industry -- recharacterizing now seems like an obvious move. But in six months, it's possible that those stocks could be back above water. Filing an extension gives you the most time to determine what your final tax liability will be before you have to decide when to include it on your return.

On the other hand, if you invested in companies that have posted only modest gains, you might decide now not to recharacterize. But in six months, it's entirely possible that a down market would make it smarter to get your do-over. With stocks including Procter & Gamble (NYSE: PG), PepsiCo (NYSE: PEP), and General Electric (NYSE: GE) in that category, getting the extension could save you from having to pay tax on lost money between now and October.

Don't wait to wait!
To get the full six months of extra time, you'll need to file Form 4868 with the IRS on or before next Monday. But that's all there is to it; you don't need to explain why you want the extension or wait for special IRS approval.

If you took advantage of the 2010 opportunity to convert your Roth, you made a smart move. But it's even smarter to maximize its value by giving yourself another six months before you have to make a final decision. If your portfolio moves strongly in either direction, then it may well lead to a much better result for your taxes.

If you're scurrying to get your returns done, get the help you need in the Fool's Tax Center.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.