Consider converting your IRA to a Roth IRA. If you had a year with less income than usual (e.g., you experienced a net operating loss or you left a well-paying job), consider a Roth Conversion. As an example, a client we met with in the first part of the year had just left his company. As a former CEO, he knew it would probably take at least a year to find his next position.
During this time, when he was without any earned income, we recommended he convert part of his IRA to a Roth IRA. In a year where he was going to be in one of the lowest tax brackets, he was able to do a Roth conversion without having to pay much in taxes. This opportunity will be gone when he finds his next job, since his salary and bonuses will push him back into the highest bracket.
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Make a gift to loved ones. If you're looking to give away assets (particularly if you have a taxable estate), consider taking advantage of your annual gift-tax exclusion. For 2015, you can gift up to $14,000 to any number of people. For married couples, that means you can gift up to $28,000 per person without having to file a gift-tax return.
Realize capital losses or capital gains. If your investments have done poorly, talk to your accountant about realizing losses. This can be a great tool to offset future capital gains by reducing your ordinary income by $3,000 a year until the losses are used up. On the flip side, consider realizing capital gains if you have less income than usual. This lets you lock in gains while paying less in taxes.