.

Stuart H. Sostmann

Portrait of Stuart H. Sostmann

With over two decades of experience as a litigator, Stuart concentrates his practice in the area of commercial general liability. He routinely handles high exposure matters in the fields of product liability, premises liability, auto liability, construction litigation, marine liability, dram shop and commercial litigation. This includes cases involving personal injuries and property damage claims.

As the Managing Attorney of the firm's third-largest office, Stuart oversees the daily operations, including the supervision of 75 employees. In addition to his managerial duties, Stuart serves as the Casualty Supervisor, where he ensures that all client matters are handled promptly, professionally, and effectively by the team of attorneys.

In his career, Stuart has represented manufacturers, suppliers and retailers in product liability matters, including electronics, medical equipment, food products, appliances, farm equipment, plumbing equipment, power tools, toys and sports and recreational equipment. He frequently represents property owners, retailers, pharmacies, general contractors, subcontractors and utilities in premises liability litigation. He has tried numerous cases to verdict in counties throughout Western Pennsylvania.

A significant portion of Stuart’s practice has been devoted to construction litigation. These cases are highly complex and require deep industry knowledge and experience. Stuart has handled a wide range of construction injury and defect cases, representing contractors, subcontractors, material suppliers, engineers, architects, and other construction professionals throughout Pennsylvania. His experience includes defending against claims involving construction defects such as water intrusion from faulty roofing or window and door seals, cracked foundations or improper waterproofing, structural and design issues, mold intrusion, drywall defects, and soil subsidence, heaving, or movement.

Stuart attended the University of Pittsburgh graduating with a B.A. in Political Science. He then attended the University of Pittsburgh School of Law where he participated in the Appellate Moot Court Program, Student Bar Association and the Health Law Certificate Program. He obtained his juris doctor from the University of Pittsburgh School of Law.

Stuart currently serves on the Marshall Dennehey Diversity, Equity and Inclusion Committee working to improve the recruitment, retention and advancement of diverse attorneys and professionals. He is the former President of the Pennsylvania Defense Institute, an organization of civil defense attorneys, executives of insurance companies and self-insured corporations. Stuart is also a member of the Allegheny County Bar Association and the Academy of Trial Lawyers of Allegheny County. Among his many honors, he is Rated AV® Preeminent™ by LexisNexis Martindale-Hubbell and is recognized among the Best Lawyers in America for his work in product liability litigation. Stuart is additionally recognized as Pennsylvania Super Lawyer.

    • University of Pittsburgh School of Law (J.D., 1999)
    • University of Pittsburgh (B.A., cum laude, 1996)
    • Pennsylvania, 1999
    • Supreme Court of the United States, 2023
    • AV® Preeminent™ by Martindale-Hubbell®
    • The Best Lawyers in America®, "Lawyer of the Year," Pittsburgh, Product Liability Litigation – Defendants (2026)
    • The Best Lawyers in America®, Product Liability Litigation - Defendants (2022-2027)
    • Pennsylvania Super Lawyers (2018-2022; 2025-2026)
    • Allegheny County Bar Association
    • American Bar Association
    • Pennsylvania Defense Institute, President 2022-2023; Executive VP of Operations 2021-2022; Executive VP of Programming 2020-2021
    • AI in the Legal Profession, Marshall Dennehey Client Presentation, September 2024
    • Civil Litigation State of Affairs – The Impact of COVID-19 in Pennsylvania and New Jersey & What’s Next, Marshall Dennehey Client Webinar, May, 2021
    • An Overview of Construction Defect Litigation in Pennsylvania, Nationwide Insurance Company, December 16, 2014
    • Commercial Defense Practice in New York, New Jersey & Pennsylvania, Nationwide Insurance Company, December 5, 2014
    • Brief Overview of Pennsylvania Contractual Indemnity and Additional Insured Issues, Nationwide Insurance Company, April 2012
    • Discoverability and Proper Use of Claim Notes, Berkley Mid-Atlantic, October 2011
    • “Yes! Waivers of Liability for Recreational Activities Are Still Effective in Pennsylvania,” Defense Digest, Vol. 23, No. 1, March 2017
    • "Timing Is Everything, Even for Bad Faith Claims," Defense Digest, Vol. 6, No. 1, February 2000 
    • Obtained a defense verdict following a three-day jury trial in a slip and fall injury case. The plaintiff slipped in the lobby of a commercial building and claimed a serious and ongoing injury to her right shoulder.  Plaintiff alleged she fell due to a wet floor caused by the facilities management’s cleaning process and the lack of sufficient visible wet floor caution signs. Plaintiff underwent two surgeries, claimed ongoing pain and suffering, and sought $500,000 prior to trial. We represented the building ownership and the facilities management company. Problematic for the defense was the lack of a surveillance video of the incident, photographs of the lobby contemporaneous to the incident, or an incident report.  Despite this, we persuaded the jury to find for the Defense by establishing a consistent and credible history of habitual practice in the placement of wet floor signs across the lobby in highly visible areas. We also won the credibility battle through our well-prepared witnesses.  Although faced with a sympathetic plaintiff with a substantiated history of medical treatment, we succeeded by presenting the case using “old school” personal injury defense tactics that were necessary due to the lack of video, photographs, and documentation.    
    • Successfully argued a precedent-setting case in the Pennsylvania Superior Court where a waiver of subrogation clause in a construction contract was applied to building damages caused by a windstorm three years after the project was completed. 
    • Successfully defended a product installer at trial in a single vehicle accident, where the placement of the product in the vehicle was claimed to be the cause of the crash at high speed.  A defense verdict was obtained after a 5 day jury trial where the demand was $800,000 prior to trial.

Results

Defense Verdict Following Jury Trial in Slip and Fall Case in the Court of Common Pleas of Allegheny County.

The plaintiff slipped in the lobby of a commercial building and claimed a serious and ongoing injury to her right shoulder. She alleged she fell due to a wet floor caused by the facilities management’s cleaning process and the lack of sufficient visible wet floor caution signs. The plaintiff underwent two surgeries, claimed ongoing pain and suffering, and sought $500,000 prior to trial.  We represented the building ownership and the facilities management company. Problematic for the defense was the lack of a surveillance video of the incident, photographs of the lobby contemporaneous to the incident, or an incident report. Despite this, we persuaded the jury to find for the defense by establishing a consistent and credible history of habitual practice in the placement of wet floor signs in highly visible areas across the lobby.  We also won the credibility battle through our well-prepared witnesses. Although faced with a sympathetic plaintiff with a substantiated history of medical treatment, our attorneys succeeded by presenting the case using “old school” personal injury defense tactics that were necessary due to the lack of video, photographs, and documentation. 

Defense Verdict Secured in Slip-and-Fall Jury Trial

We obtained a defense verdict following a three-day jury trial in a slip-and-fall injury case in the Court of Common Pleas of Allegheny County. The plaintiff slipped in the allegedly wet lobby of a commercial building and claimed a serious and ongoing injury to her right shoulder. Problematic for our case was the lack of a surveillance video of the incident, photographs of the lobby contemporaneous to the incident, or an incident report. Despite this, we persuaded the jury to find for the defense by establishing a consistent and credible history of habitual practice in the placement of wet floor signs across the lobby in highly visible areas. 

Thought Leadership

How I Made Office Managing Attorney: 'Stay True to Yourself, and Things Will Work Out to Your Benefit,' Says Stuart Sostmann of Marshall Dennehey

January 3, 2025

"When I was a younger attorney, I displayed arrogance at times to cover up various insecurities. My advice would be to stay true to yourself, and things will work out to your benefit."

Defense Digest

On the Pulse…Construction Injury Litigation Practice Group

December 1, 2023

Recent data released from the United States Bureau of Labor Statistics reveals that construction laborers accounted for 11.9% of all reported fatal falls, slips, or trips in 2020 across all occupations. Sixty percent of all construction laborers perform their work near or around moving mechanical parts or in close proximity to large moving objects. Fifty percent of these workers reportedly make use of PPE. Construction sites are among the most dangerous places to work in the United States. Indeed, in 2020 alone, construction laborers accounted for 8.9% of all workplace deaths due to exposure to harmful substances or environments. With millions of accidents reported each year, injuries to construction workers are often serious or even catastrophic.  This type of litigation is fraught with difficulty since it tends to involve sophisticated legal issues, multiple parties, multiple causes of action, complex relationships, and problematic factual situations. The law in this area continues to evolve as existing rules and precedent are continually challenged, overturned, replaced, or modified.  Marshall Dennehey’s Construction Injury Litigation Practice Group understands these complex relationships and issues. Our firm has a significant presence in the construction industry in the representation of construction companies/prime contractors, commercial property owners/ managers, developers, design professionals, and demolition, electrical, roofing, and various other trade subcontractors in a wide array of serious loss cases where there is often catastrophic injury or death. With decades of experience, our diverse team of attorneys regularly defends our clients in a multitude of personal injury matters arising out of the construction process. We handle everything from catastrophic injury or death due to contact with objects or equipment, fatal or catastrophic transportation incidents, roofing incidents, and scaffolding/ladder incidents, to the more routine worksite slip and fall incidents.  Our defense approach is aimed at the early identification of key issues and is predicated on developing the earliest possible defense strategies tailored to the individual case and client. Our involvement often begins with pre-litigation accident investigation, claims analysis, best practices related to client document and evidence retention, and early assessment of risk/liability transfer opportunities to shift liability and exposure under the terms of a construction contract, including indemnification and additional insured coverage issues. Our diverse team of trial attorneys have significant experience in handling some of the most high-profile and complex construction litigation matters taking place across the United States, and we have proven time and again, that we are ready and able to try even the most challenging construction injury matters to verdict with the skills needed to prevail.  The depth of our experience is the key to our legal defense in construction injury matters. Our professionals have considerable breadth of experience in this domain. They understand the evolving and complex laws surrounding this volatile area of practice, including issues relating to insurance coverage and claims disputes, additional insured coverage, product liability, workers’ compensation, the statutory employer doctrine, contractor licensing issues, Occupational Safety and Health Act (OSHA) compliance and workplace safety issues, and the peculiar risk doctrine. Through the use of cutting-edge technology and aggressive claim investigation, we are able to assess liability exposure and potential damages issues early on in a case so, together with the client and insurer, we can effectively resolve the case. Our unique strategy and team approach consists of experienced partners, associates, and paralegals capable of handling the basic, as well as the highly-sophisticated and complex, construction injury litigation matters throughout Pennsylvania, New Jersey, Delaware, Ohio, Florida, New York, and Connecticut.  We look forward to your inquiries and remain at your disposal for presentations or seminars your company may desire.     Defense Digest, Vol. 29, No. 4, December 2023, is prepared by Marshall Dennehey to provide information on recent legal developments of interest to our readers. This publication is not intended to provide legal advice for a specific situation or to create an attorney-client relationship. ATTORNEY ADVERTISING pursuant to New York RPC 7.1. © 2023 Marshall Dennehey. All Rights Reserved. This article may not be reprinted without the express written permission of our firm. For reprints, contact tamontemuro@mdwcg.com. 

Firm Highlights

Thought Leadership

The Tolling Trap: Filing Alone Will Not Toll the Statute Without Good-Faith Service

The Eastern District of Pennsylvania recently reinforced a critical limitation on bad faith claims, holding that a timely filing alone will not preserve a cause of action absent a good-faith effort to serve the original process. The plaintiff had presented a claim for underinsured motorist benefits to his auto insurer. The insurer evaluated the claim and determined that the plaintiff’s accident-related damages did not exceed the bodily injury liability insurance limits of the at-fault driver and denied his claim. Among other claims, the plaintiff sought to present a claim for insurance bad faith under 42 Pa. C.S.A. § 8371, to which a two year statute of limitation applies. He first filed a praecipe for writ of summons before the expiration of the statute of limitation. However, the plaintiff did not attempt to serve the praecipe or writ until after the statute of limitations had expired. Additionally, the service failed as the plaintiff had mailed the original process to an incorrect address. Despite receipt of the Postal Service’s failure to deliver the original process, the plaintiff did not attempt to re-serve the writ. Two months later, the plaintiff filed a complaint and then successfully served that complaint. The insurer sought to dismiss the plaintiff’s bad faith claim as time-barred by the statute of limitations. The district court agreed. Though the plaintiff had filed a praecipe for a writ of summons prior to the expiration of the statute of limitations, the statute is only tolled if there is a good faith effort to serve that original process. In this case, the court determined that the plaintiff had failed to perform a “good faith effort to serve the original process”. Additionally, though the filing and service of a complaint can serve as alternative original process when the lawsuit is commenced by the filing of a praecipe for a writ of summons, the plaintiff filed his complaint after the statute of limitations had expired. The plaintiff’s bad faith claim was therefore determined to be barred by the statute of limitations and dismissed by the court, with prejudice. A key takeaway for the defense is not to assume that the statute of limitations has been successfully tolled by a plaintiff merely because a praecipe for a writ of summons or complaint has been filed prior to the expiration of the statute. A filed complaint or writ is only part of the equation. The defense should carefully review the docket and filings to confirm that the plaintiff also performed the requisite good faith effort to serve that original process. A thorough review of the docket may reveal that the plaintiff failed to make the good-faith service efforts necessary to toll the statute of limitations.

Thought Leadership

Florida Supreme Court Rules Florida Statute §627.70152 Does not Apply Retroactively

In a decision that resolves years of appellate uncertainty and confirms that insurers and insureds alike can rely on the legal framework in place when a policy is issued, the Supreme Court of Florida last week found that Florida Statute §627.70152, which involves an insured’s requirement to provide an insurer with pre-suit notice before filing a suit, cannot be applied retroactively. In Universal Property & Casualty Insurance Company v. Hughes, the Court was presented with the issue of whether the statutory pre-suit notice requirement applied retroactively and whether it would apply to a breach of contract of an insurance policy that was issued before the statute went into effect. Before the Court was an appeal from a homeowner, Ms. Hughes, who sued her insurance carrier, Universal Property & Casualty Insurance Company (Universal) for breach of contract under an insurance policy that was in effect from April 24, 2019 through April 24, 2020. During the policy period, Ms. Hughes suffered a loss and, on May 29, 2019, made a claim for water damage. The carrier investigated the loss and issued payment; Ms. Hughes disputed the payment, finding the amount insufficient for repairs. On July 1, 2021, Florida Statute §627.70152 went into effect, which required insureds to provide notice of intent to initiate litigation against the carrier prior to filing a lawsuit; if an insured filed the lawsuit without complying with §627.70152, a court must dismiss the case without prejudice. On August 4, 2021, Ms. Hughes filed her lawsuit against Universal for breach of contract. Universal moved to dismiss based on her failure to comply with §627.70152. Ms. Hughes contended the notice requirement could not be applied retroactively. The trial court disagreed and dismissed the lawsuit without prejudice, and Ms. Hughes appealed. During the appeal, the Fourth District Court of Appeal, in Cole v. Universal Property & Casualty, 363 So. 3d 1089 (Fla. 4th DCA 2023), ruled that Florida Statute §627.70152 did apply retroactively to policies issued before the effective date of §627.70152. However, the Sixth District Court agreed with Ms. Hughes and overturned the trial court’s ruling, finding the statute could not retroactively apply to policies issued prior to the statute effective date. Thereafter, the other district courts weighed in, with the Third District Court agreeing with the Fourth District Court, and the First, Second and Fifth District Courts agreeing with the Sixth District Court. In resolving the conflict amongst the district courts, the Supreme Court advised “as a general rule, ‘the statute in effect at the time an insurance contract is executed governs substantive issues arising in connection with that contract.’ Hassen v. State Farm Mut. Auto. Ins. Co., 674 So. 2d 106, 108 (Fla. 1996). The Court applied the two-step test when deciding whether a statute has retroactive application: “First, the Court must ascertain whether the Legislature intended for the statute to apply retroactively. Second, if such an intent is clearly expressed, the Court must determine whether retroactive application would violate any constitutional principles.” Menendez v. Progressive Exp. Ins. Co., 35 So. 3d 873, 877 (Fla. 2010). In analyzing the Legislature’s intent, the Court must determine whether the Legislature has manifested a clear command for retroactivity in the statutory text.  In review of the statutory text, the Court found nothing in the language of the statute to indicate that the phrase “all suits” was serving another purpose of expanding its reach to suits based on policies that both predate and postdate the enactment of the statute. Buis v. Universal Prop. & Cas. Ins. Co., 394 So. 3d 738, 741 (Fla. 2d DCA 2024). Further, the Court noted the statute has an effective date, which has long been considered to be evidence against retroactive application of a statute. The Court concluded that, on its face, no provision of §627.70152 speaks to application of the statute to insurance policies issued before the statute’s effective date and therefore, the Legislature did not clearly command retroactivity of the statute to include insurance policies issued prior to the enactment of the statute. The Court briefly reviewed Universal’s argument that the presuit notice requirement was procedural, not substantive, and therefore should be applied retroactively; however, the Court agreed with the Sixth District Court’s finding that, in its entirety, §627.70152 transformed an insured’s ability to sue an insurance company under a property insurance policy and an insurer’s obligations to respond to and pay insurance claims, thus making the requirement a substantive change. The Court thereby upheld the decision of the Sixth District and disapproved the decision of the Fourth District in Cole.

Thought Leadership

Commonwealth Court Reaffirms the Constitutionality of Act 111's IRE Provisions

In this case, the claimant sustained a work injury of January 6, 1994, which was acknowledged by Notice of Compensation Payable (NCP). After the claimant’s receipt of 104 weeks of temporary total disability benefits, the employer filed a Request for an Impairment Rating Examination (IRE). The IRE was performed in May 2023 and the IRE physician found that the claimant had a 5% whole person impairment, under the AMA Guides. The employer filed a Petition based on the IRE results, and the Petition was granted by the WCJ. During litigation, the claimant argued that the IRE provisions of Act 111 (Section 306(a.3) of the Act) were not applicable to her injury, since it predated June 24, 1996, the date Act 57 went into effect, and that the IRE provisions were unconstitutional. The Workers’ Compensation Judge (WCJ)) granted the Petition and the Board affirmed. On appeal to the Commonwealth Court, the claimant argued that Act 111 violated the nondelegation doctrine and that its retroactive application to the claimant’s injury was unconstitutional. The court rejected the arguments on the basis that they had already found the same arguments without merit in multiple, prior cases. The court also addressed an argument made by the claimant that Act 111 was procedurally defective under the Pennsylvania Constitution because it was only considered on two days in each House after having undergone amendments and reassignments. The court noted that the Pennsylvania Constitution requires every bill to be considered on three different days in each House. The claimant maintained that, according to the legislative history, the bill did not receive three separate days of consideration from each House when it was assigned a new bill number. The court pointed out, however, that the bill number, H.B. 1840 remained constant and was considered on three occasions by the House. Further, the court concluded that minor amendments to the bill were germane to its original subject, which was to modify the Act’s IRE process, in accordance with Protz II.