June 15
Due date for second installment of
2012 individual estimated tax.
July 31
Due date for filing 2011 retirement or
employee benefit plan returns (5500
series) for plans on a calendar year.
September 17
Due date for third installment of 2012
individual estimated tax.
Deadline for filing 2011 calendar-year
tax returns for corporations with
extensions of the March 15 deadline.
Deadline for filing 2011 partnership
returns with extensions of the
April 17 deadline.