Puerto Rico Extends Work Product Protection to Expert Drafts and Attorney-Expert Communications

On August 6, 2026, Puerto Rico Act 172-2026 was approved to extend work product protection to draft expert reports and most attorney-expert communications—bringing the island’s expert discovery rules in line with federal practice. The new law amends Rule 23.1 of the Puerto Rico Rules of Civil Procedure and reverses the broad discovery standard that had exposed draft reports and attorney-expert communications to opposing counsel.

For years, Puerto Rico followed an open approach to expert discovery. Indeed, in McNeil Healthcare, LLC v. Municipio de Las Piedras, 206 DPR 659 (2021), the Puerto Rico Supreme Court had held that draft expert reports and communications between attorneys and their experts were not protected by work-product immunity. Opposing counsel could demand all drafts of expert reports, attorney-expert communications, and internal materials showing how the attorney’s strategic input shaped the expert’s analysis.

Act 172-2026 now shields all draft expert reports and disclosures from discovery—preliminary versions, outlines, working drafts, notes, and recordings are all protected. The Act also protects attorney-expert communications, with three narrow exceptions. Specifically, communications remain discoverable only if they: (1) relate to the expert’s compensation, (2) identify facts or data provided by the attorney that the expert considered, or (3) identify assumptions provided by the attorney that the expert relied upon. This mirrors the protections established by the Federal Rule of Civil Procedure 26(b)(4). Consistent with that federal rule, the following documents will typically remain fully discoverable under Puerto Rico’s Act 172-2026: the expert’s final report; deposition testimony; the facts and data underlying the expert’s final opinion; compensation arrangements; and attorney-provided facts, data, or assumptions the expert actually used.

For attorneys, this means candid collaboration is restored. Lawyers can now work repeatedly with experts—posing hypotheticals, testing theories, revising drafts—without fear that every email and marginal comment will be turned over to opposing counsel. Early expert analysis, including abandoned theories and provisional findings, remains confidential.

For experts, this means that preliminary thoughts and evolving opinions are now confidential, allowing them to share working hypotheses and request clarification through dialogue with counsel without creating a discoverable paper trail.

Based on this new development, discovery strategies should focus on final reports, disclosed foundational materials, and deposition testimony—including in cases already in discovery, since the Act took effect immediately—draft materials and most attorney-expert discussions are off limits.

Individuals and businesses facing litigation involving expert witnesses now benefit from strengthened protections for the collaborative process between attorney and expert. For more information on how Act 172-2026 may impact your case, feel free to contact our Commercial Litigation Team.