Every era of this series ends with a transfer of power, and the 2010s staged the strangest one yet. The decade handed the market to Wall Street algorithms, index machines, and passive flows, retiring human judgment from price-setting with barely a vote taken. By the decade’s end, most daily trading volume ran through code, growth had beaten value by more than 300 percent, and the financial press was publishing obituaries for value investing as a category. This chapter of our five-era Wall Street series covers the takeover completely, because nothing in the current market makes sense without it. The machines did not merely change trading. In fact, they changed what a price means, and one investor’s answer to that change drives every later chapter.

The Decade the Buyers Changed Species

Start with the structural fact underneath everything. Across the 2010s, the marginal buyer of American stocks stopped being a person with an opinion and became a program with a rule. Index funds automated the largest flows, buying whatever the index contained in proportion to its size. Quantitative funds traded on statistical factors, momentum, volatility, and correlation, at speeds no human could follow. High-frequency market makers intermediated nearly everything in between. Each machine class behaved rationally by its own rules. Together, however, they removed the question that had anchored markets for a century. Nobody in the new volume was asking what a business was worth. The question had not been answered badly. Rather, it had simply stopped being asked, and prices floated free of it.

The Passive Avalanche

The index revolution supplied the decade’s largest single force. Money flooded from active managers into index funds and ETFs throughout the period, a migration driven by fees, logic, and a decade of active underperformance. By the decade’s close, passive vehicles held a share of the US stock market that rivaled and then overtook traditional active management. The consequences were mechanical and enormous. Index money buys by size, so the biggest companies received the largest automatic bids regardless of valuation. Equally, anything outside the major indexes received nothing, no matter how profitable. Inclusion became destiny. A company’s membership card mattered more than its income statement, and the deeper effects of that inversion fill our file on the ETF-ization of everything.

The Rise of the Algorithms

Alongside the passive wave, the trading floor itself dissolved into code. High-frequency firms came to dominate market-making, executing in microseconds. Quant funds scaled statistical strategies across every liquid security on earth. Momentum programs, the decade’s signature species, bought whatever was rising and shorted whatever was falling, a strategy that requires no opinion about any business and profits as long as trends persist. The cast of machines and their respective diets get full treatment in our file on how algorithms price stocks. The summary belongs here. By decade’s end, the majority of volume was non-discretionary, executing rules rather than judgments. Prices still moved constantly. What moved them had changed species entirely.

What the Code Actually Reads

Understanding the takeover requires knowing the machines’ reading list, because it is short. The code consumes price, volume, momentum, volatility, short interest, options flow, and machine-readable headlines, signals that exist for every stock and update continuously. It does not read strategy, brand strength, management quality, or replacement value, the slow variables where actual business worth lives. The omission is not an oversight. Those variables resist quantification at scale, so the machines were built without them. The consequence defines the era. Companies became, to the dominant buyers, bundles of statistical properties rather than businesses. A profitable manufacturer and a doomed startup with identical chart patterns received identical treatment, since the chart was the only fact the new market could see.

The Feedback Loop

Put the pieces together and the decade’s engine appears. Index flows bid up the largest stocks automatically. Rising prices attracted momentum code, which bid them higher, which grew their index weight, which attracted more passive flow. The loop compounded for years without requiring a single human decision, and it ran in reverse simultaneously. Stocks falling out of favor lost index weight, attracted momentum shorting, and fell further, regardless of their fundamentals. Value investors call the result a two-tier market. The favored tier compounded on autopilot. Meanwhile, the orphaned tier, profitable companies outside the loop, drifted toward prices that assumed their extinction. Both tiers were priced by the same machinery, which is why both mispricings persisted. The loop had no exit built in, only an eventual collision with reality.

The 300 Percent Gap

The scoreboard made the takeover undeniable. For roughly a century, value stocks had outperformed growth stocks over long periods, the most documented pattern in market history and the foundation of several Nobel prizes. Across the thirteen years following the financial crisis, the pattern inverted violently, with growth outrunning value by more than 300 percent. Academics debated the causes. Practitioners lived them. Every mechanism in this chapter pushed the same direction, since index flows, momentum code, and the era’s interest rates all favored the large, the rising, and the long-duration story stock. The gap was not a verdict on value as a concept. It was a measurement of how completely the new buyers had replaced the old question. The full autopsy fills our file on value’s death notices.

The Loop’s Stress Tests

The decade supplied live demonstrations of the machinery’s temperament. In February 2018, volatility-linked products unwound in a single afternoon, erasing positions at a speed only code could achieve, an episode traders nicknamed for its violence. Then March 2020 staged the full exam. The pandemic crash ran faster than any human-driven decline in history, as every machine class sold simultaneously, and the recovery ran just as mechanically once the flows reversed. Both episodes shared the signature of the era. Prices moved at machine speed while business reality moved at human speed, and the gap between them opened and closed in weeks. For investors equipped to value businesses independently, each stress test was a clearance sale. The machines, of course, sent no invitations.

The Human Capital Exodus

The takeover reshaped careers as thoroughly as prices. Stock-picking jobs disappeared across the decade as active funds closed or converted, and a generation of analytical talent migrated to quantitative firms, technology companies, and private markets. The migration mattered for the public market’s metabolism. Fewer trained humans examined fewer companies each year, while the machines required engineers rather than analysts. Business schools followed the demand, teaching factor models where they once taught security analysis. By the decade’s end, the skill of valuing an ordinary public company had become genuinely scarce, a craft maintained by a shrinking guild. Scarcity, as always, repriced the skill upward. The few remaining practitioners inherited a market full of work nobody else was trained to do.

ZIRP: The Decade’s Silent Partner

One more force deserves its credit, because the machines had an accomplice in monetary policy. Near-zero interest rates persisted through most of the decade, and zero rates rewrite valuation math in growth’s favor. When money costs nothing, profits promised a decade away discount to nearly their full value, so story stocks with distant earnings compete evenly with businesses earning cash today. The regime punished exactly the investors who demanded current earnings at low multiples. Equally, cheap financing let unprofitable companies grow indefinitely, validating the momentum code that chased them. Policy did not create the machine takeover. Still, it subsidized the loop’s favorite assets for ten consecutive years, which made the era’s verdicts look far more permanent than they were.

The Death Notices for Value

By the decade’s second half, the eulogies had become a genre. Financial media published recurring features on the death of value investing, complete with charts of the widening gap and quotes from capitulating managers. Famous value funds closed or converted their mandates. Academic papers questioned whether the value factor had been arbitraged out of existence. The pressure on practitioners was professional, not merely intellectual, since allocators read the same obituaries and redeemed accordingly. Surviving the era as a value investor required either capitulation, camouflage, or conviction with unusually patient capital. The genre itself became a contrarian indicator in retrospect. Markets rarely bury a discipline at its bottom quietly. They publish the funeral, in fact, right before the resurrection.

The Coverage Desert

Beneath the headlines, a quieter collapse mattered more for this series. Wall Street research coverage of small companies evaporated across the decade. Regulation unbundled research payments, banking fees migrated to mega-cap deals, and brokerage economics stopped supporting analysts who covered micro caps. Thousands of public companies ended the decade with zero professional coverage, meaning no earnings estimates, no models, and no institutional audience. The desert compounded the machines’ blindness, because the one human function that might have corrected an algorithmic mispricing, a paid analyst noticing, had been defunded. Orphaned companies stayed orphaned indefinitely. For most investors, the desert was invisible. For a deep value specialist, it was a map of everywhere the competition had left.

The Casualties and the Contrarians

Every regime change sorts its generation, and this one sorted brutally. The casualties included value managers who capitulated at the bottom, buying the favored tier just before the regime cracked, and the funds that closed after redemptions made patience impossible. The contrarians read the same data differently. Bruce Galloway, whose career had already survived four eras, concluded that a market systematically mispricing an entire category of company was not a broken hunting ground but a stocked pond. His response, studying what the algorithms punished and supplying catalysts the code could not ignore, became the Man vs. Machine doctrine that anchors the next chapter of this series. The decade that defeated most value investors handed its survivors a larger opportunity than any era before it.

The Decade’s Legacy

The takeover never reversed, which is the legacy that matters. Passive share kept growing into the 2020s, algorithmic volume stayed dominant, and the coverage desert never refilled. What changed was the arrival of investors who treated the machines as a fixed feature to be exploited rather than a storm to be survived. The orphaned tier became a renewable resource, restocked by every panic and every index exclusion. Meanwhile, artificial intelligence began adding new algorithmic buyers while rewriting the fundamentals beneath the old code’s assumptions, a distortion the current era is still pricing. The 2010s built the machine market. Every campaign in the current portfolio is being fought on the terrain this decade left behind.

Where The Conversation Continues

The machine takeover is the era most readers lived through without seeing, which makes it the most useful chapter in the series for understanding any portfolio today. The story continues into the Man vs. Machine era, and the deeper files on the algorithms, the ETFs, and the death notices branch from this hub. Our print feature arrives in the July issue, Out East, where a decade of index returns built more than a few of the season’s larger houses. The owners might enjoy learning what actually built them. The machines, after all, never send a card.