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.