When an appeal involves legal issues that are novel or of statewide importance, appellate counsel should consider soliciting amicus curiae (friend of the court) participation in support of their client’s position. The first step is to identify potential amici who would be willing to submit an amicus brief to provide the court with information and perspectives beyond what is presented by the parties. For corporate litigants, in-house counsel can be a valuable resource for identifying potential amici and assisting appellate counsel in soliciting amicus participation.

Advocacy and interest groups are frequent amicus participants. In SanMiguel v. Grimaldi, ___ N.Y.3d ___, 2025 WL 2955744 (Oct. 21, 2025), for example, the New York Trial Lawyers’ Association, Defense Association of New York, Inc., Greater New York Hospital Association, New York State Academy of Trial Lawyers and Medical Society of the State of New York filed amicus briefs on opposing sides of a novel legal issue presented in a medical malpractice case. Many interest and trade groups have committees that search for amicus opportunities and evaluate requests for amicus participation.

The New York Court of Appeals website contains a link to weekly “New Case Filings” that lists recently filed appeals by case title, jurisdictional predicate, subject matter and key issues. Although the issues in this list are derived from Preliminary Appeal Statements processed by the clerk’s office (see Rules of the Court of Appeals section 500.9), and thus may never reach briefing or a decision on the merits, their publication may suggest motions for amicus participation to counsel whose clients are interested in the subject matter of these appeals. Indeed, the website indicates that “[t]he court welcomes motions for amicus curiae participation from those qualified and interested in the subject matter of these newly filed appeals.”

Permission By Motion Required

Under Rule 500.23, “Any nonparty other than the attorney general seeking to file an amicus brief on an appeal, certified question or motion for leave to appeal must obtain permission by motion.” Rule 500.23 was amended in 2024 to provide that “amicus curiae relief will be denied where acceptance of the amicus submission may cause the recusal or disqualification of one or more judges of the court.”

The court also amended Rule 500.23 in 2024 to address the timing of amicus curiae motions.

In normal course appeals, Rule 500.23(a)(1)(iii) generally requires service of the motion for amicus relief no later than 30 days after the filing date set for appellant’s reply brief. In appeals and certified questions selected for review by the alternative procedure, Rule 500.23(a)(2) generally requires service of the motion for amicus relief no later than 30 days after the filing date set for respondent’s submission.

An amicus may seek to participate in a motion for permission to appeal where the proposed appellant does not have an appeal as of right. Amicus support for a party’s motion for permission to appeal can be very effective in showing the court that the case presents important issues beyond the interests of the immediate parties, which is a principal ground for granting a party’s motion for permission to appeal

Rule 500.23(a)(3) prescribes the timing of motions for amicus relief on motions for permission to appeal, which is generally no later than 15 days after the return date of the leave application to which it relates. Rule 500.23(a)(3) provides that “[t]he granting of a motion to appear amicus curiae on a motion for permission to appeal does not authorize the movant to appear as an amicus on the subsequent appeal.”

Thus, to avoid this potential pitfall, the movant should specifically request two items of relief: (1) amicus participation on the motion for permission to appeal; and (2) in the event the appellant is granted permission to appeal, leave to file an amicus brief on the appeal. Absent a request for the second item of relief, the amicus must start the process over again by filing a new motion for leave to file the amicus brief on the appeal pursuant to Rule 500.23(a)(1)(iii) or 500.23(a)(2).

Criteria for the Amicus Motion

Perhaps the best evidence of the appropriateness of amicus relief from the court’s standpoint is the proposed amicus brief itself, which must be filed with the motion (Rule 500.23[a][1][i]). This requirement assists the court in assessing the relevance of the brief’s content and its trustworthiness. It also forces the amicus to assess whether the issues presented are sufficiently important to warrant the cost and effort of preparing a proposed brief with no assurance that the court will accept it. Amicus briefs must conform to the word and page limitations and other technical requirements for briefs generally (see, e.g., Rule 500.23[a][1][i]).

Rule 500.23 provides comprehensive substantive criteria for amicus motions in the Court of Appeals. The Uniform Practice Rules of the Appellate Division similarly require motions for leave to file an amicus brief (see 22 N.Y.C.R.R. §1250.4[f]), but do not provide specific guidance for such motions except to state: “An affidavit or affirmation in support of the motion shall briefly set forth the issues to be briefed and the movant’s interest in the issues, and shall include such number of copies of the proposed brief as the court requires.

The proposed brief may not duplicate arguments made by a party to the appeal or proceeding.” Court of Appeals Rule 500.23 is therefore instructive for amicus motions in the Appellate Division, especially with respect to the criteria for obtaining amicus relief.

In Court of Appeals practice, a motion for leave to file amicus briefs has three basic elements. First, the motion papers must “demonstrate that the parties are not capable of a full and adequate presentation and that movant could remedy this deficiency; movant could identify law or arguments that might otherwise escape the court’s consideration; or the proposed amicus curiae brief otherwise would be of assistance to the court” (Rule 500.23[a][4][i]).

For example, an amicus brief can be used to buttress a lesser quality brief of a party by providing a more thorough legal analysis (though seeking leave on this ground naturally requires some finesse). An amicus brief can be used to apprise the court of the far-reaching legal, social or economic implications of a decision or to provide the court with a more comprehensive legal framework for a decision, such as a nationwide survey of the law in a particular area.

Finally, an amicus brief can assist the court in cases involving highly specialized fields such as securities law or products liability law where the amicus possesses greater expertise than the parties. Whatever the reason, the goal is to convince the court that the amicus brief will assist the court in reaching its decision.

Second, after identifying the preserved issues the amicus wants to brief, the motion papers must “include a statement of the identity of movant and movant’s interest in the matter” (Rule 500.23[a][4][ii]). If the amicus is an organization, then the statement of interest should include a detailed description of its purpose, membership, activities and subject matter expertise. If the organization has previously been granted permission to file amicus briefs in other cases this should be mentioned. The motion should also explain the motivation of the amicus for wanting to participate in the appeal, including an explanation of how the outcome of the appeal might impact its members.

Third, the motion must “include a statement indicating whether: (a) a party’s counsel contributed content to the brief or participated in the preparation of the brief in any other manner; (b) a party or a party’s counsel contributed money that was intended to fund preparation or submission of the brief; and (c) a person or entity, other than movant or movant’s counsel, contributed money that was intended to fund preparation or submission of the brief and, if so, identifying each such person or entity” (Rule 500.23[a][4][iii]). The better practice is to state explicitly that no such contributions were made if this is in fact true.

This disclosure rule serves several purposes. It prevents a party’s counsel from attempting to evade the page and word limitations for briefs by drafting the amicus brief, assists the court in assessing the trustworthiness and interest of the amici, avoids the ethical conflict created when a party funds the drafting of an amicus brief in support of its position, and reinforces the corporate disclosure requirement in Rule 500.1(f). At the same time, this Rule is not meant to discourage a party’s counsel from soliciting supporting amicus briefs.

A party served with a motion for amicus relief may file opposition thereto (Rule 500.23[a][5]). Absent a compelling reason to oppose the motion, adverse parties often consent to such relief as long as the proposed amicus has a legitimate interest in the case. Virtually all timely amicus motions are granted in any event. According to the 2024 Annual Report of the Clerk of the Court of Appeals (the last year for which statistics are available), the court decided 104 motions for amicus relief in 2024. Of those, 94 (90%) were granted. This suggests that it is probably wiser for an adverse party to seek amicus support for its own position than to oppose the motion.

Effective Amicus Briefs

As noted, amicus curiae means “friend of the court.” Friends try to help, not burden, each other. A persuasive amicus brief can be an effective complement to a party’s brief and can assist the court in deciding issues that have potential ramifications beyond the present case. Conversely, while coordination of arguments is of course desirable to present a united front between amicus counsel and counsel for the party whose position the amicus supports, an amicus brief that simply echoes a party’s arguments (the 'me too' brief) or functions as a blatant lobbying effort to achieve a particular outcome only burdens the court, and, even if accepted for filing, will probably be ignored. Some attributes of effective amicus briefs are discussed below.

In most cases, the parties’ counsel will be capable of a full and adequate presentation of the issues insofar as they affect the parties’ immediate interests. In some instances, however, a party of limited resources intent on winning a particular case may make a weak presentation on a question of widespread importance.

The value of an amicus brief may lie in its ability to focus the court’s attention on law or arguments that might otherwise escape its consideration. For example, an amicus brief may reveal a problem with how a potential ruling recognizing a new cause of action would affect differently situated non-parties. Thus, an effective amicus brief may persuade the court to limit the scope of its ruling to the specific facts of the case before it to avoid unintended consequences for non-parties that would result from a broader ruling.

Amicus briefs can be used to augment a party’s analysis of a worthwhile legal issue where page or word limitations preclude an in-depth discussion by the party. For example, in a matter involving statutory interpretation, an amicus brief may add background information about the legislative history or implementation of a specific statute or statutory framework.

An amicus brief can also conduct a nationwide survey of the law to demonstrate how other jurisdictions have resolved a particular legal issue or how a proposed new rule or cause of action coincides with the majority view in other states. Both of these examples involve supplementation, not duplication, of a party’s brief.

Amicus briefs can also serve to highlight the practical implications of a decision in cases that hinge on highly technical or scientific knowledge, which explains why such briefs are regularly filed in products liability litigation. For example, an automotive trade association amicus may be in a better position than the parties to inform the court about the feasibility of a proposed product redesign or warning.

There are limits, however, to what issues and evidence can be presented in an amicus brief.

First and foremost, an amicus “shall not present issues not raised before the courts below” (Rule 500.23[a][4]). This limitation accords with the general principle that the Court of Appeals only possesses jurisdiction to review properly preserved issues. Similarly, an amicus is constrained by the record created by the parties and therefore may not introduce facts or other evidence outside the record.

Despite this limitation the court usually will consider reliable extra-record material that will promote a more fully informed decision and help prevent future unintended consequences, especially on public policy matters. Such materials may include matters of public record (e.g. legislative history) or statistics, scientific studies, academic research or social science data. These materials must be from credible and incontrovertible sources.

A well-crafted amicus brief truly assists the court in deciding novel or important issues by providing the unique perspective of the amicus and exploring the potential consequences of a decision on non-parties and society in general. This kind of amicus brief, which avoids overt party advocacy, is the one most likely to be read by and favorably influence busy appellate judges.

Reprinted with permission from New York Law Journal, © ALM Media Properties LLC. All rights reserved.