Atty. Mark D. Penner

Atty. Mark D. Penner

As a patent and trademark lawyer Toronto-based, Mark D. Penner’s practice focuses on all aspects of the acquisition, protection, enforcement and strategic use of a wide range of intellectual property assets in Canada and around the world.

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Intellectual Property Law Attorney · Serving Mississauga, ON

Profile Summary

About Mark D. Penner at a Glance

Mark D. Penner is a real estate and ip attorney based in Mississauga, Ontario, practicing at Cassels Brock & Blackwell LLP. Recognitions include Best Lawyers in America — Intellectual Property Law (2026). Serves clients in Mississauga, ON and the surrounding metropolitan area.

Verified attorney profile · Updated October 2026

About Mark D. Penner

  • As a patent and trademark lawyer Toronto-based, Mark D. Penner’s practice focuses on all aspects of the acquisition, protection, enforcement and strategic use of a wide range of intellectual property assets in Canada and around the world
  • Acting for a range of clients, from individual inventors, start-ups and other early stage companies to large multinational companies, Mark provides strategic advice in a variety of technology areas, including biotechnology, chemistry, energy, social media, insurance, communications and digital marketing
  • Mark regularly speaks and writes extensively on all aspects of intellectual property rights, particularly the commercialization of IP rights for start-ups as well as commercial matters for companies with respect to IP rights in national, cross-border and multinational commercial transactions
  • He is frequently sought after by national and international media as a commentator on IP matters

Practice Areas Explained

Mark D. Penner's Areas of Legal Practice

Each practice area below reflects the types of cases Mark D. Penner handles, with a practical overview of what that area of law involves and how it may apply to your situation in Mississauga.

Real Estate Law in Mississauga

Real estate attorneys handle home purchases, sales, commercial transactions, title disputes, and landlord-tenant matters.

Mark D. Penner is one of 313,729 real estate attorneys indexed nationally. Browse real estate attorneys in Ontario →

Intellectual Property in Mississauga

IP attorneys protect inventions, brands, and creative work through patent prosecution, trademark registration, copyright, and trade-secret enforcement.

Mark D. Penner is one of 105,285 ip attorneys indexed nationally. Browse ip attorneys in Ontario →

Jurisdictional Context

Why Local Counsel Matters in Mississauga

Practicing law in Ontario. Legal matters in Ontario are governed by state-specific rules of civil and criminal procedure, statutes of limitations, and substantive law. Cases originating in Mississauga are typically filed in the local municipal court or the appropriate Ontario state district court, depending on subject matter and amount in controversy. An attorney licensed in Ontario brings working knowledge of local procedural deadlines, judicial practices in this venue, and the substantive law that applies to cases brought here. Out-of-state attorneys generally cannot represent clients in Ontario courts without local counsel or pro hac vice admission.

Mississauga Courts and Legal Process

Choosing a Mississauga-based attorney means your counsel already knows the local docketing timelines, preferred filing formats, and how individual judges typically rule on procedural motions — details that only come from practicing in this jurisdiction day after day. That local familiarity can translate to better strategy, faster filings, and fewer costly surprises.

Looking for additional Ontario attorneys? Browse all attorneys in Mississauga or all attorneys in Ontario.

Frequently Asked

Common Questions About Mark D. Penner

Where is Mark D. Penner's law office located?
Mark D. Penner's law practice is located in Mississauga, Ontario. The firm is Cassels Brock & Blackwell LLP. You can contact the office directly through this profile page.
What practice areas does Mark D. Penner handle?
Mark D. Penner focuses on real estate, ip. Each practice area listed reflects experience handling cases of that type in Ontario.
How can I contact Mark D. Penner for a consultation?
You can contact Mark D. Penner directly through this profile page. Click "Ask the Attorney" to submit a question, or "Schedule a Consultation" to book a meeting. Most claimed-profile attorneys respond within one business day.
What awards or recognition has Mark D. Penner received?
Mark D. Penner's notable recognition includes: Best Lawyers in America — Intellectual Property Law.

Professional Profile

Why Clients in Mississauga Choose Mark D. Penner

Selecting an attorney is one of the most consequential decisions you can make when a legal matter arises. Below are the core qualities that distinguish Mark D. Penner's practice in the field of real estate and ip.

Broad Practice Area Coverage

Covering real estate and ip, Mark D. Penner can address the full spectrum of a client's legal needs without requiring referrals to separate specialists for each issue.

Local Presence in Mississauga

A Mississauga-based practice means Mark D. Penner attends hearings in the same courthouses, knows the local clerks, and understands the unwritten scheduling norms that affect every case filed here.

Case Types

Common Legal Issues Mark D. Penner Handles in Mississauga

Below is a representative sample of the types of matters Mark D. Penner has experience with under Ontario law. If your situation involves one of these case categories, this attorney may be well positioned to help you understand your options.

Residential property transactions
Real Estate
Commercial lease disputes
Real Estate
Title and deed issues
Real Estate
Landlord-tenant conflicts
Real Estate
Trademark registration
IP
Copyright infringement defense
IP
Patent prosecution
IP
Trade secret protection
IP

This list is illustrative, not exhaustive. Contact Mark D. Penner directly to discuss the specifics of your situation.

Search Reference

How People Find Mark D. Penner Online

Prospective clients searching for legal help in Mississauga commonly use a combination of the attorney's name and their specific legal need. The following search terms frequently lead people to this profile and to attorneys like Mark D. Penner.

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If any of the above matches what you searched for, you've found the right profile. Use the contact options at the top of this page to get in touch with Mark D. Penner directly.

Mark D. Penner's Practice Areas & Specializations

Awards & Professional Honors

Best Lawyers in America — Intellectual Property Law
- 2026

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