Set aside time to plan
Effective planning requires that you have a good understanding of your current tax situation, as well as a reasonable estimate of how your circumstances might change next year. There's a real opportunity for tax savings if you'll be paying taxes at a lower rate in one year than in the other. However, the window for most tax-saving moves closes on December 31, so don't procrastinate.
Defer income to next year
Consider opportunities to defer income to 2019, particularly if you think you may be in a lower tax bracket then. For example, you may be able to defer a year-end bonus or delay the collection of business debts, rents, and payments for services. Doing so may enable you to postpone payment of tax on the income until next year.
You might also look for opportunities to accelerate deductions into the current tax year. If you itemize deductions, making payments for deductible expenses such as medical expenses, qualifying interest, and state taxes before the end of the year, instead of paying them in early 2019, could make a difference on your 2018 return.
Factor in the AMT
If you're subject to the alternative minimum tax (AMT), traditional year-end maneuvers such as deferring income and accelerating deductions can have a negative effect. Essentially a separate federal income tax system with its own rates and rules, the AMT effectively disallows a number of itemized deductions. For example, if you're subject to the AMT in 2018, prepaying 2019 state and local taxes probably won't help your 2018 tax situation, but could hurt your 2019 bottom line. Taking the time to determine whether you may be subject to the AMT before you make any year-end moves could help save you from making a costly mistake.
Bump up withholding to cover a tax shortfall
If it looks as though you're going to owe federal income tax for the year, especially if you think you may be subject to an estimated tax penalty, consider asking your employer (via Form W-4) to increase your withholding for the remainder of the year to cover the shortfall. The biggest advantage in doing so is that withholding is considered as having been paid evenly through the year instead of when the dollars are actually taken from your paycheck. This strategy can also be used to make up for low or missing quarterly estimated tax payments. With all the recent tax changes, it may be especially important to review your withholding in 2018.
Maximize retirement savings
Deductible contributions to a traditional IRA and pre-tax contributions to an employer-sponsored retirement plan such as a 401(k) can reduce your 2018 taxable income. If you haven't already contributed up to the maximum amount allowed, consider doing so by year-end.
Take any required distributions
Once you reach age 70½, you generally must start taking required minimum distributions (RMDs) from traditional IRAs and employer-sponsored retirement plans (an exception may apply if you're still working for the employer sponsoring the plan). Take any distributions by the date required — the end of the year for most individuals. The penalty for failing to do so is substantial: 50% of any amount that you failed to distribute as required.
Weigh year-end investment moves
You shouldn't let tax considerations drive your investment decisions. However, it's worth considering the tax implications of any year-end investment moves that you make. For example, if you have realized net capital gains from selling securities at a profit, you might avoid being taxed on some or all of those gains by selling losing positions. Any losses over and above the amount of your gains can be used to offset up to $3,000 of ordinary income ($1,500 if your filing status is married filing separately) or carried forward to reduce your taxes in future years.
Beware the net investment income tax
Don't forget to account for the 3.8% net investment income tax. This additional tax may apply to some or all of your net investment income if your modified adjusted gross income (AGI) exceeds $200,000 ($250,000 if married filing jointly, $125,000 if married filing separately, $200,000 if head of household).
Get help if you need it
There's a lot to think about when it comes to tax planning. That's why it often makes sense to talk to a tax professional who is able to evaluate your situation and help you determine if any year-end moves make sense for you.
Timing of itemized deductions and the increased standard deduction
The Tax Cuts and Jobs Act, signed into law in December 2017, substantially increased the standard deduction amounts and made significant changes to itemized deductions, generally starting in 2018. (After 2025, these provisions revert to pre-2018 law.) It may now be especially useful to bunch itemized deductions in certain years; for example, when they would exceed the standard deduction.
IRA and retirement plan contributions
For 2018, you can contribute up to $18,500 to a 401(k) plan ($24,500 if you're age 50 or older) and up to $5,500 to a traditional or Roth IRA ($6,500 if you're age 50 or older). The window to make 2018 contributions to an employer plan generally closes at the end of the year, while you typically have until the due date of your federal income tax return (not including extensions) to make 2018 IRA contributions.