Credit relationships determine access

In the foreign exchange market, the common retail narrative focuses on liquidity providers, spreads, and execution speeds. But beneath that surface lies a far more fundamental determinant of who gets what: credit relationships. Access to the interbank market is not a technical problem. It is a credit problem. Understanding this distinction separates casual traders from those who grasp how the market actually moves money.

The Tier 1 interbank market is not a public utility. It is a permissioned network where participants must first establish bilateral credit lines before they can trade with one another. These credit lines are the gatekeepers of liquidity. Without a credit relationship, a bank cannot access the best available prices from another bank. The result is a market structured not by open competition but by a web of private agreements that dictate who can trade, at what size, and at what cost.

The Hierarchy of Access

At the top of the market structure sit the largest global banks—Deutsche Bank, JP Morgan, Citigroup, UBS, and a handful of others. These institutions maintain credit relationships with one another across multiple currencies and jurisdictions. They form the inner circle of the interbank market. Because they trust each other’s creditworthiness, they extend the tightest spreads and the deepest liquidity. A trade between two Tier 1 banks on a major pair like EUR/USD might cost less than a tenth of a pip.

The moment you move to a smaller bank, a regional lender, or a non-bank market maker, the credit picture changes. These institutions may have credit lines with only a subset of the Tier 1 banks. Their access is narrower. They cannot see the same depth of book. Their counterparties may impose caps on trade size or require pre-trade credit checks. The spreads they receive are wider because the risk premium embedded in the credit relationship is higher.

For a retail trader, this hierarchy is invisible. Your broker aggregates prices from several liquidity providers and passes them to you as a single feed. But that feed is only as good as the credit relationships your broker maintains. If your broker has thin credit lines with Tier 1 banks, the prices you see will be marked up. You are not trading the interbank market. You are trading a filtered version of it, shaped by your broker’s credit standing.

Liquidity Is Not a Commodity

A common mistake is to think of liquidity as a homogeneous resource available at a button’s press. It is not. Liquidity is contingent on trust. When a bank quotes a price, it is extending credit. It agrees to deliver the currency at that price based on the assumption that the counterparty will settle. If a bank doubts a counterparty’s ability to settle, it widens the spread or withdraws the quote.

This dynamic becomes stark during periods of stress. In March 2020, as COVID-19 triggered a dollar funding crisis, credit lines froze. Banks pulled quotes. Spreads on major pairs widened to levels not seen since the 2008 crisis. The problem was not a lack of dollars. The problem was that banks stopped trusting each other’s ability to repay. Credit relationships collapsed, and with them, the liquidity that usually flows freely through the interbank market.

For casual investors, this history is not abstract. It explains why certain strategies fail during high volatility. A stop-loss order that works in calm markets may not execute at the expected level when liquidity evaporates. The underlying cause is not just volatility but the breakdown of credit relationships that normally provide continuous pricing.

How Market Makers Exploit Structure

Large banks do not merely participate in the interbank market. They also act as gatekeepers. By controlling which counterparties receive prime brokerage access, they shape the entire market structure. A hedge fund or smaller broker must go through a prime broker to access the interbank market. That prime broker extends credit to the client, takes on the settlement risk, and charges for it. The prime broker also monitors the client’s position sizes, leverage, and collateral. If the client looks shaky, the credit line is reduced or revoked.

This creates a pyramid of access. At the base are millions of retail traders. Above them are brokers, then prime brokers, then the Tier 1 banks. Each layer extracts a cost from the layer below, justified by the credit risk taken. The retail trader pays the highest cost, not because of malice, but because the credit relationship that permits their trade to exist is the most expensive in the chain.

Practical Implications for Traders

Understanding credit-based market structure changes how you evaluate a broker. The best brokers are not simply those with low advertised spreads. They are those with strong credit relationships in the interbank market. A broker that has multiple prime brokerage relationships and direct lines to Tier 1 banks can offer tighter, more stable pricing. A broker that relies on a single aggregator or a second-tier liquidity provider will pass on higher costs, especially during news events or illiquid sessions.

You should also recognize that your own creditworthiness matters. While retail traders do not negotiate credit lines, your behavior affects your broker’s risk management. High leverage, rapid scalping, and concentrated positions increase the credit risk your broker bears. In response, your broker may widen your spreads or delay execution. This is not a conspiracy. It is the market structure working as designed.

The interbank market is not a democracy. It is a credit club. Admission is granted by relationship, not by capital. The liquidity you see is a byproduct of trust. And trust is the scarcest resource in the entire system. Treat it accordingly.