Sigourney R. Haylock
Overview
Sigourney is a litigator who focuses her practice on defending companies in high-stakes commercial litigation. She has particular experience representing clients in the retail and consumer products, food and beverage, real estate, and healthcare sectors.
Career & Education
- University of California, Santa Barbara, B.A., Environmental Studies, Minor in Global Peace and Security, 2012
- Loyola Law School, Los Angeles, J.D., 2017
- California
- U.S. District Court for the Central District of California
Sigourney's Insights
Firm News | 1 min read | 10.29.25
Crowell Secures Victory for Mondelēz in False Advertising Alleged “Greenwashing” Suit
Chicago – October 29, 2025: Crowell & Moring secured a complete dismissal with prejudice of a proposed class action suit on behalf of Mondelēz, LLC in the Northern District of Illinois.
Client Alert | 11.17.23
Client Alert | 4 min read | 10.10.23
Client Alert | 2 min read | 09.21.23
Representative Matters
- Defeated consumer class action filed against a snacking company in N.D. Ill. alleging false advertising and greenwashing over “climate neutral certified” labeling on a food company’s brand of snack bars. All claims were dismissed with prejudice, with the judge agreeing the truthful certification statement was non-deceptive and plaintiff faced no risk of future harm.
- Represented a bakery-café against false advertising claims (clean), resulting in two successful motions to dismiss and a positive resolution.
- Represented manufacturer of personal care products in multi-plaintiff suit regarding consumer complaints of skin irritation, hair thinning, and hair loss resulting in dismissal.
- Defended a fashion retailer in litigation regarding co-tenancy and lease termination issues, resulting in a favorable settlement at mediation.
- Counseled companies whose products were alleged to contain various Proposition 65-listed chemicals on regulatory compliance and threatened litigation.
- Assisted in Prop 65 compliance counselling and violation notice investigations for companies whose products were alleged to contain various listed chemicals including lead and lead compounds, mercury, acrylamide, hexavalent chromium, DEHP and DINP.
- Represented a medical device manufacturer in mass tort federal and state products liability suits alleging design and warnings defects, fraud, and breach of warranties.
Sigourney's Insights
Firm News | 1 min read | 10.29.25
Crowell Secures Victory for Mondelēz in False Advertising Alleged “Greenwashing” Suit
Chicago – October 29, 2025: Crowell & Moring secured a complete dismissal with prejudice of a proposed class action suit on behalf of Mondelēz, LLC in the Northern District of Illinois.
Client Alert | 11.17.23
Client Alert | 4 min read | 10.10.23
Client Alert | 2 min read | 09.21.23
Insights
Commercial Lease Disputes During the Ongoing Pandemic: The Second Wave
|09.15.21
Crowell & Moring’s Retail & Consumer Products Law Observer
Sigourney's Insights
Firm News | 1 min read | 10.29.25
Crowell Secures Victory for Mondelēz in False Advertising Alleged “Greenwashing” Suit
Chicago – October 29, 2025: Crowell & Moring secured a complete dismissal with prejudice of a proposed class action suit on behalf of Mondelēz, LLC in the Northern District of Illinois.
Client Alert | 11.17.23
Client Alert | 4 min read | 10.10.23
Client Alert | 2 min read | 09.21.23




