If you received a large refund after filing your 2017 income tax return, you’re probably enjoying the influx of cash. But a large refund isn’t all positive. It also means you were essentially giving the government an interest-free loan.

That’s why a large refund for the previous tax year would usually indicate that you should consider reducing the amounts you’re having withheld (and/or what estimated tax payments you’re making) for the current year. But 2018 is a little different.

To avoid interest and penalties, you must make sufficient federal income tax payments long before your April filing deadline through withholding, estimated tax payments, or a combination of the two. The third 2018 estimated tax payment deadline for individuals is September 17.

If you don’t have an employer withholding tax from your pay, you likely need to make estimated tax payments. But even if you do have withholding, you might need to pay estimated tax. It can be necessary if you have more than a nominal amount of income from sources such as self-employment, interest, dividends, alimony, rent, prizes, awards or the sales of assets.

Here are some of the key tax-related deadlines affecting businesses and other employers during the third quarter of 2017. Keep in mind that this list isn’t all-inclusive, so there may be additional deadlines that apply to you. Contact us to ensure you’re meeting all applicable deadlines and to learn more about the filing requirements.