The Market Structure That Now Controls Asset Prices w/ Michael Green
Summary
- The market structure has fundamentally shifted from 80% active management in 1995 to less than 10% today. The majority of trading is now dominated by passive index strategies and the statistical arbitrage that supports them.
- "Passive" investing is misnamed; it is actually a systematic momentum algorithm. When these funds receive cash, they blindly buy companies in proportion to market capitalization, regardless of valuation.
- Retail trading has exploded to 17-20% of market volume, driven by commission-free models funded by Payment for Order Flow (PFOF).
- Asset prices are increasingly determined by liquidity flows (inflows to Vanguard/BlackRock) and mechanical hedging (delta hedging by market makers) rather than fundamental analysis.
Trade Ideas
Green explains that "index arbitrage" is the single largest hedge fund strategy, citing "Tesla soaring prior to inclusion in the S&P 500" as the prime example. Price action in large-cap names is often driven by funds front-running mandatory index buying rather than fundamental improvements. While the S&P inclusion trade is in the past for Tesla, the stock remains a proxy for how index mechanics distort valuation. NEUTRAL. The easy "inclusion arbitrage" money has been made, but the stock is now supported by the passive bid described in the SPY thesis. If passive flows reverse, high-beta constituents like TSLA suffer from the same mechanical selling pressure.
Green notes that commission-free trading is funded by Payment for Order Flow (PFOF), stating, "I believe Citadel pays about $4 billion a year to Robin Hood so they can see what the Robin Hood retail traders are doing." With retail trading now comprising 17-20% of the market (up from 10% in 1995), the "facilitators" of this volume are the primary beneficiaries. Robinhood monetizes the user base regardless of whether the users make money. LONG. The business model is validated by the massive checks written by market makers like Citadel to access retail flow. Regulatory changes to PFOF or a decline in retail trading participation.
Michael Green
Portfolio Manager at Simplify Asset Management
Green states that passive strategies act as a "systematic algorithm" where "did you give me cash? If so then buy everything in proportion to its market capitalization." He notes that 85 cents of every retirement dollar now flows into these strategies. Because these vehicles receive "ungodly amounts of cash" daily (Vanguard raises Simplify's total AUM every week), there is a persistent, price-insensitive bid under the largest market-cap stocks. As long as net flows are positive, the indices are mathematically forced to drift higher. LONG the S&P 500 (SPY) to align with the dominant mechanical flow of capital. A reversal in flows (net redemptions) would trigger the algorithm to sell indiscriminately ("passive sell pressure"), though the trigger for this was asked but not answered in the provided text.
Michael Green
Portfolio Manager at Simplify Asset Management
Green describes the mechanics of retail flow: "If the retail traders want to bid up GameStop... We're going to need to buy more GameStop." He explains that market makers are "delta hedging," buying the stock simply to offset the risk of call options sold to retail. The price movement is mechanical. Market makers do not care if the company is good or bad; they are forced to buy when retail buys options (gamma squeeze). This creates explosive volatility disconnected from fundamentals. WATCH. This is a structural play on volatility and retail sentiment, not an investment in the business. Once retail option volume dries up, the mechanical bid from market makers disappears, leading to rapid mean reversion.
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This Milk Road Daily video, published February 08, 2026, features Michael Green discussing TSLA, HOOD, SPY, GME. 4 trade ideas extracted by AI with direction and confidence scoring.
Speakers: Michael Green · Tickers: TSLA, HOOD, SPY, GME