in Re Navistar, Inc., 501 S.W.3d 136

Navistar manufactured International trucks with 0.5 L 13-liter MaxxForce EGR engines; Americorp bought 15 such trucks and sued Navistar alleging defects (EGR system failures) and related warranty and fraud claims.
The EPA’s 2010 emissions rules required 0.2 g NOx; Navistar pursued (but abandoned) a 0.2 NOx engine using EGR and used emissions credits to certify the 0.5 engines.
The SEC separately investigated and sued Navistar International Corp. for allegedly misleading investors about development problems with the 0.2 engine; discovery from that SEC matter was produced in federal court.
Americorp sought discovery in its suit against Navistar of depositions, sworn statements, and documents produced in the SEC litigation concerning the 0.2 engine (Requests for Production Nos. 13–15 and Interrogatory No. 1).
The trial court ordered Navistar to produce the SEC-related materials; Navistar petitioned this court for mandamus relief arguing the discovery was irrelevant (different product) and confidential because it arose from a governmental investigation.
The Court of Appeals denied mandamus, holding the SEC materials were sufficiently connected to Americorp’s claims (both engines used EGR and employees compared the engines), confidentiality objections were unsupported, and a protective order could address disclosure concerns.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Scope of discovery as to different product (0.2 engine)	SEC materials relevant because they relate to EGR issues central to Americorp's claims	Discovery regarding a product never sold/used by Americorp (0.2 engine) is irrelevant and overbroad	Court: Not an abuse — connection exists (both use EGR; internal comparisons; Navistar previously sought same materials)
Confidentiality of SEC investigation materials	SEC probe relevance outweighs confidentiality; protective order available	SEC materials are highly confidential and should be shielded from discovery	Court: Navistar failed to show privilege/confidentiality; protective order can limit use; production permitted
Whether trial court exceeded prior discovery scope/orders	Prior orders did not cover SEC investigation, so court exceeded scope	The specific requests sought SEC materials and March/May orders required production	Court: The SEC material was specifically requested and ordered; no abuse shown
Appropriateness of mandamus relief	Americorp: discovery is proper and reviewable on appeal	Navistar: mandamus warranted because discovery compels irrelevant/confidential material and appeal would be inadequate	Court: Mandamus denied — Navistar failed to show abuse of discretion or lack of adequate appellate remedy

Walker v. Packer, 827 S.W.2d 833 (Tex. 1992) (mandamus standard for abuse of discretion and adequate appellate remedy)
In re Prudential Ins. Co. of Am., 148 S.W.3d 124 (Tex. 2004) (mandamus prerequisites)
In re CSX Corp., 124 S.W.3d 149 (Tex. 2003) (burden on relator for mandamus)
In re Deere & Co., 299 S.W.3d 819 (Tex. 2009) (discovery scope in product-liability cases)
In re Graco Children’s Prods., Inc., 210 S.W.3d 598 (Tex. 2006) (limits on discovery of products plaintiff did not use)
Texaco, Inc. v. Sanderson, 898 S.W.2d 813 (Tex. 1995) (discovery must be relevant and reasonable in scope)
Ford Motor Co. v. Castillo, 279 S.W.3d 656 (Tex. 2009) (broad construction of relevance; discovery for merits)
In re Nat’l Lloyds Ins. Co., 449 S.W.3d 486 (Tex. 2014) (mandamus for discovery beyond procedural bounds)
In re Colonial Pipeline Co., 968 S.W.2d 938 (Tex. 1998) (trial court’s latitude in discovery control)