Employers must send out W-2 Forms and 1099 Forms to employees and non-employees who provide services.
If you claimed exemption from income tax withholding on the W-4 Form you gave your employer last year, you must file a new Form W-4 by this date to continue your exemption for another year.
Businesses must file paper copies of Form 1099 with the Internal Revenue Service.
Partnerships must file for 1065 for the calendar year and pay any taxes due. S Corporations must file form 1120S for the calendar year and pay any taxes due.
2017 individual income tax returns due, along with any tax, interest, and penalties due. Last day to contribute to a traditional IRA, Roth IRA, or SEP-IRA for the 2017 tax year. Estimated tax for the 1st quarter of 2018 due for those who do not pay their income tax throughout the year through withholding. C Corporations must file form 1120 for the calendar year and pay any taxes due.