As there can often be a delay of several months between the time that briefs are filed and oral argument is held, there are times when a party may want to supplement the authorities in its brief with a decision that came out after briefing was completed.  The Michigan Supreme Court, Court of Appeals, and Sixth Circuit all have specific procedures for doing just that.

Michigan Supreme Court and Court of Appeals

Submitting supplemental authority in the Michigan Supreme Court and Court of Appeals is governed by MCR 7.212(F). 1  The rule explains that without leave of court, a party may submit a "one-page communication" titled "supplemental authority," subject to certain conditions.  First, it must be for the purpose of  "call[ing] the court's attention to new authority released after the party filed its brief." 2  Second, a supplemental authority "may not raise new issues." 3  Third, it "may only discuss how the new authority applies to the case, and may not repeat arguments or authorities contained in the party's brief." 4  Finally, a supplemental authority "may not cite unpublished opinions." 5

As further explained in the Court of Appeals' Internal Operating Procedures (IOPs):

Such a filing may only cite and discuss new published authority released subsequent to the date the party filed its last brief or supplemental authority. New issues may not be raised in a supplemental authority. The body of the supplemental authority cannot exceed one page. The caption may be on a preceding page and the signature block alone may be on a subsequent page. But the text of the supplemental authority cannot exceed one page. 6

Should a party seek to exceed the one-page limit or cite newly-discovered authority that was released before the party filed its brief, then a motion is required: 

Unless accompanied by a motion, a supplemental authority will be returned if it (1) fails to comply with the requirement that it not exceed one page, (2) cites other than new published authority. 7

Finally, the IOPs provide one last word of caution.  A supplemental authority must include all new authorities that the party wishes to raise.  In other words, multiple supplemental authorities are not permitted, unless "a party files a supplemental authority after the filing of the brief, and then another new case is released after filing of the first supplemental authority." 8  In that case, "the subsequent supplemental authority will be accepted." 9

Note that neither MCR 7.212(F) nor the IOP specifically provide for a response to a supplemental authority filing.  Doing so, however, is simply a matter of the opposing party filing its own "supplemental authority" addressing the new case.

Sixth Circuit

Supplemental authority filings in the Sixth Circuit are governed by FR Civ P 28(j).  The rule provides that a party may "promptly advise the circuit court clerk by letter" of any "pertinent and significant authorities [that] come to a party's attention after the party's brief has been filed—or after oral argument but before decision."  Although the rule does not expressly restrict a party to citing decisions issued after the party's brief has been filed, it would be wise to use caution in citing decisions that were simply overlooked.  The letter must "state the reasons for the supplemental citations, referring either to the page of the brief or to a point argued orally."  Thus, it should go without saying that a Rule 28(j) letter may not be used to raise new issues.  Finally, the "body of the letter must not exceed 350 words." A party wishing to respond to a Rule 28(j) letter must do so "promptly" in a letter that it is "similarly limited."


1     MCR 7.312(I), which governs supplemental authority in the Supreme Court, provides that a party may file "a supplemental authority in conformity with MCR 7.212(F)."

2     MCR 7.212(F).

3     MCR 7.212(F)(1).

4     MCR 7.212(F)(2).

5     MCR 7.212(F)(3).

6     IOP 7.212(F)-1 (emphasis in original).

7     Id.

8     Id. (emphasis in original).

9     Id.

A version of this article was previously published in the Michigan Defense Quarterly, Vol. 37, No. 3 (2021).

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.