US retail brokers received roughly US$340 million in payment for order flow in May, with Robinhood and Charles Schwab leading the payouts, according to figures compiled by Global Trading.

The May number renews a debate that never fully closed. Payment for order flow — the practice by which brokers route retail orders to wholesale market makers in exchange for cash — remains the economic backbone of zero-commission retail execution in US equities and options. A $340 million monthly aggregate shows the economics at scale, and it puts the two largest retail franchises at the top of the distribution.

Why does a monthly PFOF figure matter to desks?

For buy-side and sell-side participants, the PFOF aggregate is a market-structure signal in three respects.

• Execution quality benchmarking. Retail flow sold to wholesalers is internalized rather than displayed on exchanges. The larger the internalized pool, the greater the share of US equity volume that never touches the lit book, which affects price discovery and the reference prices institutional orders interact with.
• Routing concentration. Robinhood and Schwab leading the tally indicates where the largest blocks of retail order flow concentrate among a small set of wholesale market makers. That concentration is a standing concern for regulators examining competition in wholesale market making.
• Broker economics. For zero-commission brokers, PFOF is a core revenue line. A $340 million month across the industry quantifies the incentive structure that determines routing decisions — decisions made under best-execution obligations, not revenue maximization, at least on paper.

What is mandated versus what is asserted?

Two things should be separated when reading the May figure.

Mandated: brokers must conduct regular and rigorous reviews of execution quality, and Rule 606 disclosure reports must detail payment arrangements and routing venues. The $340 million aggregate is built from that disclosure regime.

Asserted: the industry position that PFOF lets brokers offer commission-free trading while retail investors receive price improvement at or inside the displayed quote. Critics counter that internalization fragments liquidity and that payments can skew routing. The May tally does not, by itself, resolve either claim. What it measures is dollars flowing from wholesalers to brokers. What it does not measure is whether the executing quality received by retail traders matches or beats the alternatives.

Who pays, and what does the flow cost?

The counterparties in this market are the wholesale market makers who internalize retail orders — firms that profit from the spread and hedge the resulting inventory. The $340 million paid in May represents a fraction of the economics those firms capture, and it functions as an acquisition and retention cost for the brokers receiving it.

For technology and compliance teams, monthly PFOF disclosures feed execution-quality analytics, best-ex committees, and routing models. A rising aggregate suggests retail engagement remains robust and that internalized volume continues to claim a significant share of overall US equity trading — a structural fact institutional traders must price into their own execution strategies.

What comes next?

Global Trading's May compilation follows the sector through a period in which regulators have repeatedly examined internalization and payment practices without banning them. Successive monthly figures — June and beyond — will show whether the May payout level holds, and the annual Rule 606 refreshes will give desks the venue-level detail needed to test routing claims against execution outcomes.