SOURCES

Filings and company results (chapters 4, 5, 8, 11, 12)

• Blue Apron Holdings, Inc. Prospectus (Form 424B4), June 28, 2017; Form 10-Q for the first quarter of 2018; first quarter 2018 results; fourth quarter and full year 2022 results; agreement to be acquired by Wonder, September 2023; completion of the tender offer, November 2023. CNNMoney on the range cut, June 28, 2017.
• Chewy, Inc. Fourth quarter and fiscal year 2025 results, March 2026; Form S-1, 2019, for the definition of Autoship customer sales; Autoship terms, read September 2026.
• Peloton Interactive, Inc. Results for the second, third and fourth quarters of fiscal 2026, for the churn definition and values.

Research on subscriptions and retention offers (chapters 2, 3, 6, 8, 9, 11, 12)

• Stefano DellaVigna and Ulrike Malmendier. “Paying Not to Go to the Gym.” American Economic Review 96(3), 2006.
• Liran Einav, Ben Klopack and Neale Mahoney. “Selling Subscriptions.” American Economic Review 115(5), 2025. Author copy.
• Adam Miller, Navdeep Sahni and Avner Strulov-Shlain. “Sophisticated Consumers with Inertia: Long-Term Implications from a Large-Scale Field Experiment.” Working paper, version of January 2026.
• Michael Lewis. “Customer Acquisition Promotions and Customer Asset Value.” Journal of Marketing Research 43(2), 2006.
• Hannes Datta, Bram Foubert and Harald J. Van Heerde. “The Challenge of Retaining Customers Acquired with Free Trials.” Journal of Marketing Research 52(2), 2015.
• Eva Ascarza, Raghuram Iyengar and Martin Schleicher. “The Perils of Proactive Churn Prevention Using Plan Recommendations.” Journal of Marketing Research 53(1), 2016.
• Eva Ascarza. “Retention Futility: Targeting High-Risk Customers Might Be Ineffective.” Journal of Marketing Research 55(1), 2018.
• Raghuram Iyengar, Young-Hoon Park and Qi Yu. “The Impact of Subscription Programs on Customer Purchases.” Journal of Marketing Research, 2022.
• Ran Kivetz, Oleg Urminsky and Yuhuang Zheng. “The Goal-Gradient Hypothesis Resurrected.” Journal of Marketing Research 43(1), 2006. Joseph C. Nunes and Xavier Drèze, “The Endowed Progress Effect.” Journal of Consumer Research 32(4), 2006.
• Tony Chen, Ken Fenyo, Sylvia Yang and Jessica Zhang. “Thinking inside the subscription box: New research on e-commerce consumers.” McKinsey & Company, February 2018.

Law and card-network rules (chapters 2, 7, 10)

• Restore Online Shoppers’ Confidence Act, 15 U.S.C. § 8403.
• Federal Trade Commission. Final click-to-cancel rule, October 16, 2024; Negative Option Rule docket; conforming rule, February 12, 2026; advance notice of proposed rulemaking, March 13, 2026.
• Custom Communications, Inc. v. FTC, No. 24-3137 (8th Cir. July 8, 2025).
• Federal Trade Commission. Settlement with Amazon, September 25, 2025; amended complaint, September 2023. Chegg, September 2025. Shutterstock, May 2026. Amended complaint against Uber, December 2025.
• US Department of Justice. Adobe settlement, March 13, 2026.
• California Business and Professions Code § 17602, as amended by AB 2863 (2024); California Attorney General consumer alert, 2025.
• Minnesota Statutes § 325G.57, § 325G.58 and § 325G.60; effective date per Kelley Drye’s 2025 round-up.
• New York General Business Law § 527-a, as amended in 2025; Kelley Drye on the amendment.
• Visa. New rules for subscription merchants, 2020; rules for declined transaction resubmission, effective April 2021; Visa Account Updater FAQ; on network tokens; Visa tokens surpass physical cards, August 2022.
• Mastercard. Automatic Billing Updater. Consumer Reports on the 2019 free-trial rule. Merchant advice codes and retry fees as documented by processors and acquirers: Braintree, Yuno, Adyen on scheme fees, Adyen on Visa integrity fees, TabaPay and TD Bank, 2026. Adyen, on network tokens, 2023.

Vendor data (chapters 5, 6, 8, 9, 10, 11, 13)

• Recharge. “Subscription churn is front-loaded”, 2026; on first-order discounts, July 2026; on $0.99 first orders, August 2026; “The quarterly upgrade”, August 2026; Subscription Trend Report 2026; 2023 State of Subscription Commerce; on pause, 2023.
• Recurly. Churn rate benchmarks, July 2026 data; guide to decline reasons; on pausing, 2020; 2026 State of Subscriptions, January 2026.
• Stripe. “How we built it: Smart Retries”, January 2024; Stripe Billing; Smart Retries documentation.
• Chargebee. Subscription retention insights, updated 2024.
• Amazon. Subscribe & Save for sellers, read September 2026.
• Bloomberg Second Measure. Blue Apron customer retention, June 2016; meal kit customer retention, January 2023.