The 80/20 Rule of Gun Supply

In the late 1800s, Italian economist Vilfredo Pareto was harvesting peas in his garden when he noticed something peculiar: About 20% of the peapods produced roughly 80% of the peas. He later observed the same pattern in broader society, finding that roughly 20% of Italy’s population owned 80% of the land throughout the country. That insight became the foundation of what we now call the Pareto Principle, or the law of the vital few: A small number of causes often drive most of the consequences.

More than a century later, the law of the vital few helps explain many of the key dynamics of gun violence in America. A small network of people in a handful of neighborhoods are typically responsible for an outsize share of violence in many U.S. cities. In one study led by sociologist Andrew Papachristos, about 70% of all nonfatal gunshot injuries in Chicago occurred within social networks containing just 6% of the city’s population. A 2024 review documented similar Pareto-style dynamics in Dallas, Boston, Minneapolis, Indianapolis and Buffalo. In New York City, researchers found that shootings cluster in patterns that closely mirror the Pareto Principle, particularly in northern Manhattan, northern to southeastern Bronx and central-to-northern Brooklyn.

The same principle applies to the gun markets that fuel our country’s unique brand of violence. While the majority of licensed gun dealers in the U.S. operate legally, a small fraction are responsible for feeding the lion’s share of the illegal supply. One estimate suggests that just 5% of dealers are linked to nearly 90% of crime guns recovered by law enforcement. These are the weapons that drive interpersonal gun violence in the U.S., pushing our national homicide rate orders of magnitude higher than any other high-income nation. Pareto’s peas and property may feel far removed from the modern gun debate, but his insight still offers guidance: If we want to curb gun violence using a supply-side strategy, we should start by focusing on the small group of dealers doing the most harm.

How legal guns fuel illegal violence

Every firearm in the United States — whether manufactured domestically or imported — enters the market legally, through a licensed seller with a federal firearms license. (The exception to this rule is “ghost guns,” which are built from kits containing unassembled gun parts or constructed using components made with a 3D printer). But most guns used in violent crime are not purchased legally by the people who use them. In fact, surveys of prisoners who possessed a gun while committing a crime find that 90% to 97% of the guns were obtained through secondary channels. These secondary channels are fueled by straw purchases (where one person buys a gun for someone else who is often barred from possession); theft from homes, vehicles or gun stores; unlicensed street sales; or guns that are simply lost and never recovered.

Think of firearm dealers as faucets at the top of a vast distribution system. They’re the legal points of entry where guns begin to flow into the broader market. Most faucets work as intended. But some are left running, faulty or deliberately misused. These are the negligent dealers. They manipulate paperwork, overlook obvious red flags or intentionally look the other way on straw purchases. Over time, these dealers contribute to an ever-growing pool of firearms on the secondary market, available with relative ease to those looking to skirt legal markets. Yesterday’s bad-faith dealer is responsible for tomorrow’s gun violence.

When oversight is weak and accountability is minimal, guns leak into places they were never meant to go. Some of those leaks are intentional, like straw purchasers diverting guns into the hands of those prohibited from owning them. Then there’s unlicensed dealing, where illegal sellers operate entirely outside the system, tapping into the flow to feed underground markets via high-volume dealers, middlemen and one-off transactions. With more than 400 million guns in circulation and limited enforcement capacity, the pressure on the system is immense. Leaks turn into floods. And downstream, it’s often the most disadvantaged communities that bear the brunt.

Sure, we could pour resources into endlessly repairing the leaks that spring throughout the system — but doesn’t it make more sense to fix the faucets?

In recent years, we’ve seen clear examples of how a small number of dealers can fuel illegal gun markets. In South and Northeast Philadelphia, just six retailers sold more than 11,000 weapons between 2014 and 2020 that were later recovered at crime scenes or seized from people who obtained them illegally. A 2021 report found about 1.2% of Pennsylvania’s licensed firearm dealers accounted for 57% of firearms that ended up at crime scenes through illegal resale or straw purchases.

Even with limited access to firearms tracing data, a 2022 letter from the House Oversight and Reform Committee to the Federal Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) detailed a small number of dealers in Florida, Georgia, Indiana and Michigan responsible for a high proportion of crime guns. Whether you call them negligent, “bad apples” or just careless with paperwork, it’s hard to deny that a small group of dealers plays an outsize role in supplying the guns that fuel everyday violence.

From oversight to action

If we know where the leaks are, the next step is obvious: Fix the source. That means holding gun dealers accountable, closing well-documented gaps in oversight and investing in the agencies tasked with enforcement. These upstream interventions must come before downstream efforts to contain the damage. Without stopping the flow of guns into the illegal market, efforts to disrupt trafficking networks or reduce shootings will remain reactive and incomplete.

What’s needed is a coordinated strategy that aligns federal, state and local authorities. A layered approach led by the ATF and reinforced by state policies and local action is not duplicative. It’s resilient against failure at any one level. There is no doubt that this is politically and logistically difficult, but it’s the key to moving forward.

In recent years, there has been some progress at the federal level. In 2021, the Biden administration implemented a zero-tolerance policy for gun dealers who willfully violated core regulations. The ATF was directed to revoke licenses for dealers guilty of any of five serious violations, including falsifying records or selling firearms without conducting background checks. This resulted in the steepest increase in license revocations in the agency’s history, driven largely by the kind of serious dealer violations that result in guns being diverted toward illegal channels.

Yet in a reminder of how fragile regulatory gains can be, the ATF announced in April 2025 that it would abandon the zero-tolerance policy under the newly installed Trump administration. The message was clear: Even when oversight improves, it can be swiftly undone.

The ATF is the only federal agency responsible for regulating gun commerce, but it is consistently undermined. It has suffered from years of unstable leadership, chronic underfunding and a shortage of specialized field agents that conduct dealer inspections. There are about 80,000 gun dealers around the country, more than the combined total of McDonald’s, Burger King, Subway and Wendy’s locations. Many are “kitchen table” dealers that run out of people’s homes with no storefront. Yet federal data show that the ATF inspects only about 15% of licensed gun dealers each year. This means that most dealers are visited just once every seven years, simply because there aren’t enough agents to conduct regular inspections.

Without a consistent audit strategy and meaningful follow-up, we will continue to miss the small proportion of dealers who account for a disproportionate share of crime guns. Strengthening ATF capacity is not a threat to lawful gun ownership — it’s the best way to protect it. With proper resources, authority and staffing, the ATF can target lawbreaking dealers while ensuring that those playing by the rules are not penalized.

It’s not just about hiring more people to build better capacity — there is a real technological opportunity for improvement. In an era of big data and AI, the ATF should leverage machine learning to analyze firearms tracing data and flag dealers linked to disproportionately high numbers of crime guns or unusually short time-to-crime patterns. By integrating inspection reports, trace results and transaction records, and applying techniques like natural language processing and predictive modeling, the agency could more effectively prioritize inspections and enforcement. Moving toward 21st century solutions is essential to meet the scale of the problem, especially given the availability of relevant data, although challenges like poor digitization, data silos and legal restrictions must be addressed.

Reform also means removing structural barriers. For instance, the 2003 Tiahrt Amendment prohibits the ATF from sharing firearms tracing data with the public and restricts its ability to require dealer inventory audits. Repealing or revising the Tiahrt Amendment would allow the ATF to work more closely with local and state law enforcement, providing the intelligence needed to identify high-risk dealers before more guns end up in the wrong hands.

In the absence of strong federal enforcement, states can and should step in. Many still do not require dealers to obtain a state-specific license, nor do they enforce uniform standards for inventory control, recordkeeping or physical security. But evidence shows that states with stronger dealer oversight have less gun trafficking across state lines and lower rates of firearm homicide. States may not have the ATF’s infrastructure, but they can create the proper policy environment to deter illegal conduct, support compliance and ultimately save lives.

Local jurisdictions also have a role to play — particularly where preemption laws don’t block municipal capacity to enact localized firearm regulations. Local law enforcement can work with ATF agents to trace guns, identify patterns of dealer misconduct and pursue repeat offenders. In cities with the authority to pass additional regulations, local ordinances can restrict reckless dealer behavior and mandate responsible business practices.

Across all levels of government, the goal should be the same: to identify and disrupt the small number of dealers responsible for the most harm. The law of the vital few should guide actions across the board.

The guns already out there

While these recommendations focus on preventing future diversion, they don’t address the 400 million firearms already in circulation — many of which are untracked or illegally possessed. That’s the elephant in the room: No matter how tightly we regulate dealers moving forward, the vast existing stock of guns poses a serious risk.

One of the most effective strategies for managing this risk is requiring secure storage of firearms. The most secure form of firearm storage is locked, unloaded and separate from ammunition. Child access prevention (CAP) laws, which vary by state, generally require gun owners to lock their firearms when not in use and hold owners accountable if a shooting occurs due to negligent storage. These laws are associated with reductions in suicides, violent crime and unintentional shootings. CAP laws can also prevent theft, keeping guns already in circulation from flowing into the secondary market.

We also need better infrastructure for safe gun disposal. Many people inherit firearms, receive them as gifts or simply no longer want them — but they have no idea what to do with them. Without better options, they keep them. Proper disposal can be complicated, and most people don’t have a reliable vendor or service to handle it. Traditional gun buybacks in the U.S. are often limited and underfunded, while research has shown that they don’t directly reduce violent crime. But reducing crime isn’t their only potential benefit. Buybacks and disposal programs can also shrink the pool of guns that might be lost, stolen or diverted into secondary markets. New disposal models could make a bigger impact — such as mail-in disposal kits, drop-off programs at retailers or community centers, or modest tax incentives for relinquishing firearms. With more innovative and accessible options, fewer unwanted guns would remain in homes where they pose a risk of misuse or theft.

Finally, only 15 states and the District of Columbia currently require individuals to report lost or stolen guns, even though these weapons are frequently used in crimes. A federal law already mandates that dealers report missing firearms within 48 hours. Extending this requirement to private owners could help stem the flow of guns into criminal markets. Research suggests that public reporting of stolen guns increases when people are aware of mandatory requirements, but more data are needed to assess the impact of these laws on firearm recovery and crime prevention.

These strategies won’t solve everything. But they acknowledge a basic truth: Preventing future harm requires not only regulating future sales, but also reducing the risk posed by the enormous and poorly monitored supply of guns that already exists.

Market control, not gun control

This strategic approach isn’t about taking guns away from law-abiding citizens. Instead, it’s about imposing basic accountability on a commercial market that has operated with far too little of it. In nearly every other high-risk industry — automobiles, pharmaceuticals, alcohol — we accept regulation as necessary to protect public safety. Yet when it comes to firearms, we allow a small number of dealers to violate rules, supply illegal markets and fuel community violence with little oversight and few consequences. This should be unacceptable to all of us, but especially to the firearm owners, dealers and manufacturers that are doing the right thing and following the law.

If we want fewer shootings, we need fewer guns leaking into the wrong hands.

The law of the vital few tells us that a small number of sources account for a disproportionate share of harm. We need to shut down the worst dealers and build systems that keep the next wave of guns out of the illegal pipeline. This isn’t gun control — it’s proper market control. And it provides an actionable path toward real public safety.