January 16 – Due date for the fourth installment of 2017 individual estimated tax.

January 31 –

• Due date for employers to furnish W-2 statements to employees, and to file Forms W-2 with the Social Security Administration (both paper and electronic forms).
• Due date for payers to provide most Forms 1099-MISC with non-employee compensation in box 7 to recipients and to the IRS.
• Employers must file 2017 federal unemployment tax returns and pay any tax due.
• Due date for providers to send Forms 1095 to recipients and the IRS.