Top 5 Fraud Schemes Costing Marketplaces Millions

In the bustling world of online marketplaces, where buyers and sellers connect seamlessly, marketplace fraud lurks as a persistent threat. From seller fraud involving fake listings to buyer fraud like refund abuse, these schemes are draining millions from platforms and eroding user trust. As e-commerce continues to grow, understanding these risks is crucial for operators seeking effective marketplace verification tools to safeguard their ecosystems.

This how-to guide explores the top five fraud schemes impacting marketplaces today, backed by real-world statistics on losses and prevalence. We'll also discuss how advanced solutions, like those from Ambriel, use anomaly detection and multi-account monitoring to combat these issues. Whether you're running a marketplace or simply shopping on one, arming yourself with knowledge is the first step toward prevention.

1. Fake Listings and Seller Fraud

Seller fraud, particularly through fake listings, tops the list of marketplace fraud schemes. Fraudsters create bogus product postings—often for high-demand items like electronics or luxury goods—using stolen images and descriptions to lure buyers. Once payment is received, the "seller" disappears, leaving buyers empty-handed and platforms dealing with disputes.

This type of marketplace fraud not only leads to direct revenue losses but also damages platform reputation. According to recent data, global e-commerce fraud losses reached $44.3 billion in 2024, with seller fraud contributing significantly through counterfeit goods and non-delivery scams. In one analysis, up to one-third of ads on major marketplaces could be scams, amplifying losses in inventory and customer trust.

2. Referral and Promotion Abuse

Referral abuse occurs when fraudsters exploit incentive programs, creating multiple fake accounts to claim bonuses, discounts, or rewards repeatedly. This buyer fraud variant inflates marketing costs and skews user acquisition metrics, costing marketplaces millions in low-ROI campaigns.

Statistics highlight its rapid growth: Promotion abuse was reported as the fastest-growing threat, with 52% of companies noting an increase as early as 2021, and it's only accelerated since. In 2024, such schemes contributed to broader e-commerce losses, projected to climb to $107 billion by 2029. Marketplaces lose not just on fraudulent payouts but also through eroded pricing integrity.

3. Chargeback Fraud

Chargeback fraud, often disguised as "friendly fraud," happens when buyers dispute legitimate transactions after receiving goods, claiming issues like non-delivery or unauthorized use. This forces marketplaces to refund payments while absorbing processing fees and lost merchandise.

The financial toll is staggering: Chargebacks are expected to cost merchants over $100 billion in 2025, with 61% of disputes stemming from friendly fraud. In 2024 alone, businesses lost $8.9 billion to chargebacks, a figure set to rise amid increasing consumer familiarity with dispute processes.

Effective marketplace verification tools are key to mitigation. Ambriel's anomaly pattern recognition scans transaction histories for red flags, like frequent disputes from the same users, helping platforms challenge invalid claims and reduce overall losses.

4. Refund Abuse

Similar to chargebacks but often internal to the platform, refund abuse involves buyers exploiting return policies—claiming items weren't received or were defective—to get free products. This buyer fraud erodes profit margins and strains seller relationships.

Recent surveys show refund abuse as a top fraud attack, with a significant percentage of merchants reporting increasing rates. It contributes to the broader $44.3 billion in e-commerce fraud losses for 2024, particularly in high-volume marketplaces. Policy abuse like this can lead to revenue leakage and higher operational costs.

Ambriel combats refund abuse through cross-channel insights and behavioral monitoring, detecting patterns like serial refunders or coordinated abuse rings to automate blocks and preserve platform integrity.

5. Account Takeovers (ATO)

Account takeovers represent a sophisticated form of buyer and seller fraud where cybercriminals hijack user profiles using stolen credentials to make unauthorized purchases, sell fake items, or drain stored payment methods.

ATO attacks surged by 131% in the second half of 2022 compared to the first half of 2021, remaining a major threat into 2024 and beyond. This scheme fuels broader marketplace fraud, contributing to the projected $107 billion in global losses by 2029. Victims face identity theft, while platforms handle the fallout from disputes and lost trust.

Ambriel's tools shine in preventing ATOs by employing multi-account behavior analysis and real-time anomaly detection, such as unusual login patterns or device changes, to secure accounts proactively.

How Ambriel Empowers Marketplaces Against Fraud

Facing these escalating threats, marketplaces can't afford reactive measures. Ambriel's fraud prevention suite integrates AI-driven marketplace verification tools to identify multi-account behavior and anomaly patterns across sessions. By leveraging machine learning, our platform processes vast data sets to predict and prevent schemes like those outlined above, reducing false positives and enhancing user experience.

For instance, in detecting referral abuse or ATOs, Ambriel cross-references user actions with historical benchmarks, flagging deviations instantly. This not only cuts losses but also builds a safer ecosystem for genuine buyers and sellers.

Protecting Your Marketplace: Next Steps

Marketplace fraud—from seller fraud to buyer fraud—continues to cost millions, with global projections soaring. By staying informed and adopting advanced tools, platforms can turn the tide. If you're ready to fortify your defenses with proven marketplace verification tools, explore Ambriel's solutions today. Contact us for a demo and discover how we can help you detect anomalies and multi-account threats before they impact your bottom line.

This post is part of our How-To series on combating fraud in digital spaces. Check back for more practical guides!