September 2019 Individual Due Dates

September 1 – 2019 Fall and 2020

September 10 – Report Tips to Employer
If you are an employee who works for tips and received more than $20 in tips during August, you are required to report them to your employer on IRS Form 4070 no later than September 10. Your employer is required to withhold FICA taxes and income tax withholding for these tips from your regular wages. If your regular wages are insufficient to cover the FICA and tax withholding, the employer will report the amount of the uncollected withholding in box 12 of your W-2 for the year. You will be required to pay the uncollected withholding when your return for the year is filed.

September 16 – Estimated Tax Payment Due
The third installment of 2019 individual estimated taxes is due. Our tax system is a “pay-asyou-earn” system. To facilitate that concept, the government has provided several means of assisting taxpayers in meeting the “pay-as-you-earn” requirement.

These include:

  • Payroll withholding for employees;
  • Pension withholding for retirees; and
  • Estimated tax payments for self-employed individuals and those with other sources of income not covered by withholding.

When a taxpayer fails to prepay a safe harbor (minimum) amount, they can be subject to the underpayment penalty. This penalty is equal to the federal short-term rate plus 3 percentage points, and the penalty is computed on a quarter-by-quarter basis. Federal tax law does provide ways to avoid the underpayment penalty. If the underpayment is less than $1,000 (the de minimis amount), no penalty is assessed. In addition, the law provides “safe harbor” prepayments. There are two safe harbors:

  • The first safe harbor is based on the tax owed in the current year. If your payments equal or exceed 90% of what is owed in the current year, you can escape a penalty.
  • The second safe harbor is based on the tax owed in the immediately preceding tax year. This safe harbor is generally 100% of the prior year’s tax liability. However, for taxpayers whose AGI exceeds $150,000 ($75,000 for married taxpayers filing separately), the prior year’s safe harbor is 110%.

Example: Suppose your tax for the year is $10,000 and your prepayments total $5,600. The result is that you owe an additional $4,400 on your tax return. To find out if you owe a penalty, see if you meet the first safe harbor exception. Since 90% of $10,000 is $9,000, your prepayments fell short of the mark. You can’t avoid the penalty under this exception.

However, in the above example, the safe harbor may still apply. Assume your prior year’s tax was $5,000. Since you prepaid $5,600, which is greater than 110% of the prior year’s tax (110% = $5,500), you qualify for this safe harbor and can escape the penalty.

This example underscores the importance of making sure your prepayments are adequate, especially if you have a large increase in income. This is common when there is a large gain from the sale of stocks, sale of property, when large bonuses are paid, when a taxpayer retires, etc. Timely payment of each required estimated tax installment is also a requirement to meet the safe harbor exception to the penalty. If you have questions regarding your safe harbor estimates, please call this office as soon as possible.

CAUTION: Some state de minimis amounts and safe harbor estimate rules are different than those for the Federal estimates. Please call this office for particular state safe harbor rules.

September 2019 Business Due Dates

September 16 – S Corporations
File a 2018 calendar year income tax return (Form 1120S) and pay any tax due. This due date applies only if you requested an automatic 6-month extension. Provide each shareholder with a copy of K-1 (Form 1120S) or a substitute Schedule K-1.

September 16 – Corporations
Deposit the third installment of estimated income tax for 2019 for calendar year September 16 – Social Security, Medicare and withheld income tax If the monthly deposit rule applies, deposit the tax for payments in August.

September 16 – Nonpayroll Withholding
If the monthly deposit rule applies, deposit the tax for payments in August.

September 16 – Partnerships
File a 2018 calendar year return (Form 1065). This due date applies only if you were given an additional 5-month extension. Provide each partner with a copy of K-1 (Form 1065) or a substitute Schedule K-1.

September 30 – Fiduciaries of Estates and Trusts
File a 2018 calendar year return (Form 1041). This due date applies only if you were given an extension of 5 1/2 months. If applicable, provide each beneficiary with a copy of K-1 (Form 1041) or a substitute Schedule K-1.


Isler Northwest LLC is a firm of certified public accountants and business advisors based in Portland, Oregon. Our local, regional, and global resources, our expertise, and our emphasis on innovative solutions and continuity create value for our clients. Our service goals at Isler Northwest is to earn our clients trust as their primary business and financial advisors.

Isler Northwest

(503) 224-5321

1300 SW 5th Avenue
Suite 2900
Portland, Oregon 97201