A History of Interest and How It Moves Markets

There is a number that sits at the center of every financial decision ever made. It determines whether you build a factory or keep your money in a vault. It decides whether governments wage wars or accept peace. It is the reason some generations get rich owning houses while others can barely afford to rent. That number is the interest rate, the price of time itself.

Most people think of interest as the fee a bank charges on a loan. But that is only its most visible form. At a deeper level, an interest rate is the answer to a fundamental question: how much more is something worth today than tomorrow? The answer to that question shapes everything: stock prices, bond yields, gold, real estate, the dollar, and the rotation of capital across every corner of the global economy.

To understand how interest rates move markets, we first need to understand where they came from.

Part I: The History of Interest

The First Lenders: Mesopotamia and the Code of Hammurabi

Interest is older than coins. It is older than writing. Archaeological evidence suggests that lending at interest was practiced in Mesopotamia as far back as 3000 BC, perhaps even earlier. The instrument was grain. A farmer borrowed a fixed amount of barley in spring, promising to return more at harvest. The surplus was the interest, a compensation for the risk the lender took, and for the time value of consumption deferred.

By the time of the Code of Hammurabi, around 1754 BC, interest had become formalized enough to require legal regulation. Hammurabi set maximum rates: 33% per year on grain loans, 20% on silver. These were not arbitrary numbers. Grain loans carried higher rates because grain was perishable and the harvest uncertain. Silver was more stable and so cost less to borrow. Even then, the risk premium was built into the price of credit.

This is the first and most durable lesson in the history of interest: it is not a moral category. It is a price. And like all prices, it reflects information about risk, scarcity, and expectations of the future.

Aristotle, the Church, and the War on Usury

The ancient Greeks had a more ambivalent relationship with interest. Aristotle, in his Politics, made the argument that would echo through Western civilization for two thousand years: money is sterile. A coin cannot reproduce itself. To charge for the use of money is therefore unnatural, as though you are selling something that does not exist, the passage of time.

The early Christian Church absorbed this argument and elevated it to doctrine. The Council of Nicaea in 325 AD prohibited clergy from lending at interest. Subsequent councils extended the ban to all Christians. By the medieval period, charging interest (usury, as it was called without distinction of rate) was a mortal sin. The reasoning was theological: time belongs to God. To charge for time is to sell what is not yours.

This created one of history's great economic workarounds. If Christians could not lend at interest, someone else had to. Jews, excluded from most professions and from owning land, filled the role. The image of the Jewish moneylender that Shakespeare crystallized in Shylock was not invented by prejudice alone. It was the direct product of a theological prohibition that forced one community to perform a function that society could not do without.

The Church's ban also spawned extraordinary creativity in financial engineering. Italian merchants invented the bill of exchange, a credit instrument that created time between purchase and payment without technically charging interest. They invented the commenda, a profit-sharing partnership that looked like equity but functioned like debt. The Medici built one of the largest banking empires in European history by finding every available path around a rule that could not be enforced without destroying commerce.

The Renaissance and the Return of Legitimate Credit

By the fifteenth and sixteenth centuries, the intellectual ground was shifting. The Protestant Reformation broke the Church's monopoly on moral authority. Calvin acknowledged, cautiously, that moderate interest on commercial loans was not sinful. What mattered was the purpose and the rate, not the act itself. This single theological concession helped unlock northern European capitalism.

In Venice, Genoa, and Florence, public banks began issuing government bonds (the Monte Comune, the funded debt of the city-state) which paid investors a fixed annual return. These were interest-bearing instruments in all but name, sanctioned by the state. The distinction between usury and legitimate finance was no longer theological but practical: were you financing productive activity or simply exploiting a desperate borrower?

This is the distinction that still underlies modern financial regulation. The usury laws that most jurisdictions retain today (caps on consumer lending rates) are the direct descendants of Hammurabi's code, filtered through two thousand years of theological and philosophical argument.

Amsterdam and the First Modern Bond Market

The Dutch Republic in the seventeenth century took the next decisive step. The city of Amsterdam issued long-term government bonds, perpetual annuities called renten, which could be bought and sold on the secondary market. For the first time, interest rates became a market price, not just a negotiated contract between two parties.

The Amsterdam bond market created something new: a yield curve. Different instruments with different maturities traded at different rates. Short-term credit cost more than long-term because the uncertainty was greater. The market was, in effect, computing the collective expectation of future conditions, the first instance of what we now call price discovery in rates.

The Dutch East India Company, the world's first joint-stock corporation, combined equity and debt in ways that are recognizably modern. Investors could hold shares in the company's profits or lend it money at fixed rates. The interaction between these two forms of capital, and their relative pricing, laid the conceptual foundation for modern portfolio theory three centuries before Harry Markowitz wrote it down.

The Bank of England and the Institutionalization of the Rate

As we covered in the previous article, the Bank of England was founded in 1694 as a vehicle for financing the Crown's wars. But it quickly became something more important: the institution that set the price of money for the entire British economy.

The Bank Rate, the rate at which the Bank of England lent to other banks, became the fulcrum around which all other rates moved. If the Bank raised its rate, credit became more expensive throughout the system. Lending contracted. Business activity slowed. If it lowered the rate, credit flowed more freely and activity expanded. This was the birth of monetary policy as a lever of economic management, though it would take another two centuries before anyone understood it clearly enough to use it deliberately.

The critical insight that emerged from this period is one that remains central today: the short-term interest rate is a policy instrument. It is not discovered by the market. It is set by an authority. All other rates in the economy are negotiated relative to this anchor.

The Gold Standard Era: Interest as Discipline

Under the gold standard, central banks had limited discretion over interest rates. The rules of the system were simple and brutal: if gold flowed out of the country, you raised rates to attract it back. If gold flowed in, you could afford to lower them. Interest was not a tool of growth management. It was the mechanism by which external balance was maintained.

This created extraordinary long-run price stability at the cost of periodic economic agony. The deflations of the 1870s and 1890s, the periods that produced the American Populist movement and William Jennings Bryan's 'cross of gold' speech, were the direct result of a monetary system in which the supply of money could not expand as fast as the economy demanded. Farmers and debtors watched the real value of their obligations grow year by year without any recourse.

The gold standard also produced one of the most important empirical observations in monetary history: tight money kills growth. When credit is scarce and expensive, investment falls. When investment falls, employment falls. When employment falls, demand falls. The feedback loop can become self-reinforcing in ways that no individual actor can break on their own, which is why, in the depths of the Great Depression, every country eventually abandoned the gold standard regardless of ideological commitment.

1913: The Federal Reserve and the Modern Framework

The Federal Reserve was created in 1913 following the Panic of 1907, in which J.P. Morgan personally organized a private bailout of the American banking system because there was no public institution capable of doing so. The new institution was designed to provide exactly what the gold standard could not: an elastic currency that could expand to meet demand in a crisis without requiring gold inflows.

The Fed's founding mandate was modest: prevent banking panics and provide liquidity. It took the catastrophe of the 1930s to reveal how much more was possible, and how much damage could be done by getting policy wrong. Milton Friedman and Anna Schwartz's definitive study showed that the Federal Reserve had transformed a severe recession into the Great Depression by allowing the money supply to contract by one third between 1929 and 1933. The Fed did not cause the crash, but it turned a forest fire into a continental conflagration.

The lesson that central bankers drew from this experience, one they have never forgotten, is that in a deflationary crisis, rates must go to zero and money must be created freely. This lesson shaped every major policy response of the past century, from Bernanke's reaction to 2008 to Powell's reaction to 2020.

The Great Inflation and Volcker's Shock

The postwar Bretton Woods era was, in interest rate terms, a period of unusual calm. Rates were low and stable. The 1960s were prosperous. Then came the breakdown of Bretton Woods, the oil shocks of 1973 and 1979, and the Great Inflation, the decade in which the United States learned what happens when a central bank loses credibility.

By 1979, US inflation had reached 13.3%. The dollar was in freefall. Financial markets were effectively pricing in the permanent erosion of the purchasing power of money. President Carter appointed Paul Volcker as Fed Chairman with a single mandate: break inflation, whatever it costs.

Volcker raised the federal funds rate to 20% in June 1981. Twenty percent. This is a number so extraordinary that it is difficult to comprehend from the perspective of the 2010s and early 2020s. Mortgages cost 18%. Small businesses could not borrow. A severe double-dip recession followed. Unemployment hit 10.8% in late 1982.

But it worked. Inflation collapsed. And with it, the foundation was laid for the greatest bull market in financial history, a four-decade decline in interest rates from 20% to zero that inflated the price of virtually every asset on earth.

The Long Descent: 1981–2021

From the peak of 20% in 1981, US interest rates fell, with interruptions but relentlessly, for forty years. This single trajectory is the most important macro fact of the late twentieth and early twenty-first centuries. It explains the rise of private equity, the explosion of mortgage debt, the tech bubble, the housing bubble, the bond bull market, and the extraordinary returns of passive equity investing in that era.

When rates fall, the present value of future cash flows rises. A company that will earn $100 in ten years is worth much more when discounted at 3% than at 10%. The entire logic of modern equity valuation, including the price-to-earnings ratio, the discounted cash flow model and terminal value calculation, is exquisitely sensitive to the discount rate. And for forty years, that rate moved in only one direction.

The financial crisis of 2008 took rates to zero. The COVID shock of 2020 brought them back to zero again. By 2021, more than $18 trillion in global bonds were trading at negative nominal yields. Investors were paying governments to hold their money. The logic of the centuries had been inverted: time had no price. Or rather, its price had gone negative.

The inflation of 2021 to 2023, the most aggressive rate-hiking cycle in forty years, was the reckoning for this era. The Fed raised rates from zero to over 5% in fourteen months, then held them there as it waited for inflation to return toward its 2% target. The first cuts came in September 2024. By December 2025, the Fed had cut three times across the final quarter of the year, bringing the target range down to 3.5%–3.75%. The justification was a softening labor market rather than a decisive victory over inflation, a distinction that three dissenting FOMC members found uncomfortable enough to vote against the December cut.

As of March 2026, the cutting cycle has paused. The Fed held rates unchanged at both its January and March meetings, citing a new complicating factor: an oil shock driven by the conflict in Iran, which has pushed energy prices sharply higher and raised the risk that the last mile of disinflation stalls or reverses. The dot plot still pencils in one cut for 2026, likely in the second half of the year, after Jerome Powell's term expires in May and a new chair takes over. But the distribution of outcomes has widened considerably. We are, as of today, in a monetary policy environment that is neither clearly tightening nor clearly easing, a genuine pause suspended between the cycle that ended and the one that has not yet begun.

Part II: How Interest Rates Move Asset Classes

Understanding the history of interest is interesting. Understanding how interest rates move asset prices is useful. The two parts of this article connect in one central idea: the interest rate is the universal solvent of finance. It dissolves into the price of everything.

The mechanism is the discount rate. Every financial asset is, at its core, a claim on future cash flows. Stocks are claims on future earnings. Bonds are claims on future coupon payments and principal. Real estate is a claim on future rents. Gold is different, paying no cash flow, which is precisely what makes it interesting as a rates trade.

When rates rise, the present value of future cash flows falls. When rates fall, it rises. That is the first law of rates and asset prices. But the second law is more nuanced: different assets respond to rates differently, at different points in the economic cycle, and through different transmission mechanisms.

Bonds: The Direct Relationship

Bonds are the most straightforward case. The math is mechanical: bond prices move inversely to yields. If you own a bond paying 3% and new bonds are issued at 5%, your bond is worth less, and buyers will only purchase it at a discount large enough to bring its effective yield up to match the market. The longer the maturity of the bond, the larger the price move for a given change in rates. This is duration.

This direct mathematical relationship means bonds are simultaneously the most rate-sensitive asset class and the most reliable hedge in a deflationary recession. When growth slows and the central bank cuts rates, bond prices rise. This is why institutional portfolios have historically held a mix of equities and long-duration bonds, since the two assets tend to move in opposite directions when the economy weakens.

But this relationship broke down spectacularly in 2022. Inflation forced the Fed to raise rates aggressively even as growth slowed. Long-duration Treasury bonds lost more than 30% of their value, a drawdown that exceeded many equity bear markets. The traditional 60/40 portfolio lost both its equity and bond components simultaneously, for the first time since the 1970s. This is the inflation regime: when bonds stop being a hedge because the enemy is not recession but rising prices, every portfolio allocation has to be rethought.

The key variables for bonds in a rate cycle are: the direction of rates (are we hiking or cutting?), the shape of the yield curve (steep, flat, or inverted?), and credit spreads (the premium that corporate bonds pay over government bonds). In a late-cycle environment, as we will see, even when rates stabilize, credit spreads tend to widen, creating losses on corporate bonds even when Treasuries are stable.

Equities: Duration Assets in Disguise

Stocks are often treated as if they are immune to interest rates, particularly growth stocks, which are sold on the narrative of their future potential rather than current earnings. This is a dangerous misunderstanding. A growth stock with most of its value in earnings ten or fifteen years from now is one of the most duration-sensitive instruments in financial markets. It is, in effect, a very long-duration bond in disguise.

The 2022 rate shock provided the most dramatic illustration of this in a generation. The Nasdaq fell 33% in 2022, while the S&P 500 fell 19%. The companies that fell the most were not necessarily those with the weakest businesses. They were those with the highest valuations relative to current earnings, the longest-duration assets. Companies like Peloton, Zoom, and scores of high-multiple growth names lost 70% to 90% of their value as the discount rate moved from near-zero to 5%.

But the relationship between rates and equities is not simply negative. It depends on why rates are moving. There are two very different scenarios:

Rates rising because the economy is strong: In this case, rising rates reflect higher nominal growth, better corporate earnings, and tighter labor markets. Equities can rise alongside rates. Indeed, this is the classic early-to-mid cycle dynamic. The earnings growth more than offsets the higher discount rate.

Rates rising because inflation is high: Here, the central bank is tightening to slow the economy. Earnings expectations fall as growth decelerates. The discount rate rises and the numerator, future earnings, falls simultaneously. This is the toxic combination that produces serious equity bear markets.

The distinction is everything for sector allocation, which is where the real money in equity investing is made.

Equity Sector Rotation: The Clock Analogy

Professional asset allocators have long used a simplified mental model of how sectors perform across the interest rate and economic cycle. It is sometimes called the investment clock or sector rotation model. The idea is that different sectors of the economy are exposed to different combinations of growth and inflation, and as the macro environment rotates through its phases, sector leadership changes in a broadly predictable pattern.

Let me walk through the four key phases:

Early cycle: rates falling, growth recovering

The central bank has cut rates aggressively in response to a recession. Credit is loosening. Consumer confidence is recovering but not yet euphoric. This is historically the best environment for cyclical consumer discretionary stocks, financials, and real estate. Banks benefit from the steepening yield curve (they borrow short, lend long). Homebuilders and mortgage companies benefit from falling rates. Consumer discretionary benefits as households feel richer and more confident.

Technology also tends to perform well in early cycle. Falling rates push up the present value of future earnings, and tech companies, with their high margins and long-duration cash flows, are particularly sensitive to this re-rating.

Mid cycle: rates stable to rising, growth strong

The economy is expanding. Employment is rising. Corporate earnings are growing. The central bank has moved from crisis-mode cuts to a more neutral stance, and may be beginning to raise rates gradually. This is classically the best environment for industrials, materials, and energy. Capital spending is rising. Commodity demand is accelerating. The global growth engine is running hot.

In equity terms, value often outperforms growth in this phase. Earnings are being delivered today, not promised tomorrow. The discount rate matters less when the numerator, current earnings, is large and growing.

Late cycle: rates high, growth slowing

The central bank has tightened aggressively. Credit conditions are restrictive. The yield curve is flat or inverted, meaning short-term rates exceed long-term rates, because the market expects the central bank will eventually have to cut in response to a slowdown. Corporate margins are being squeezed by higher input costs and higher financing costs. Earnings growth is decelerating.

In this environment, defensive sectors outperform: healthcare, consumer staples, utilities. These businesses have stable, non-cyclical revenues. People buy food, medicines, and electricity regardless of the economic cycle. Their dividends become more attractive relative to equities with falling earnings. Energy sometimes continues to outperform in this phase if commodity prices remain elevated.

Growth stocks and high-multiple tech are most vulnerable here. The combination of a high discount rate and decelerating earnings is lethal to valuations built on future promise.

Recession and rate cuts: growth collapsing, rates falling

The central bank pivots. Rates are cut aggressively. The economy is contracting. Unemployment is rising. This is the worst phase for equities overall, but within that environment, some sectors are dramatically worse than others. Financials are hit hard by loan losses and margin compression. Industrials and materials suffer as capital spending collapses. Energy falls with commodity demand.

Long-duration government bonds perform best in this phase, the bond bull market moment. Within equities, quality companies with strong balance sheets, low debt, and stable earnings (often found in healthcare and staples) provide relative shelter.

Then the cycle turns again. Rates reach their low. Stimulus begins to flow. Credit conditions loosen. And the early cycle rotation begins once more.

Gold and Commodities: The Inflation Hedge

Gold occupies a unique position in the rates framework because it pays no cash flow. It has no earnings, no dividend, no coupon. This means its valuation is almost entirely a function of the opportunity cost of holding it, which is, precisely, the real interest rate.

The real interest rate is the nominal rate minus inflation. When real rates are negative, when inflation exceeds the return on cash and short-term bonds, gold becomes attractive because everything else is losing purchasing power in real terms. When real rates are positive and rising, gold loses its relative appeal because investors can earn a real return from safe assets without holding a non-yielding metal.

The relationship is remarkably consistent historically. The gold bull market of the 1970s corresponded to the period of deeply negative real rates produced by high inflation and accommodative policy. The gold bear market of the 1980s and 1990s corresponded to Volcker's high real rates and subsequent disinflation. The gold bull market of 2001 to 2011 corresponded to the era of low and falling real rates. The gold rally of 2019 to 2020 corresponded to zero nominal rates and QE.

The extraordinary gold performance of 2024 and 2025 has complicated this framework somewhat. Gold has risen even as real rates have remained relatively elevated, driven in part by central bank buying from non-Western institutions seeking to reduce dollar exposure, and by geopolitical uncertainty. This suggests that gold's traditional real rate sensitivity is being overlaid by a structural shift in reserve diversification. It does not negate the framework, but it adds a layer.

Broader commodities, including oil, copper, and agricultural products, are more directly tied to economic growth than to rates per se. They tend to do best in mid-to-late cycle, when growth is strong and inflation is rising. They are the classic inflation hedge within a portfolio, performing when stocks and bonds are both struggling with rising price pressures.

The Yield Curve: The Map of the Cycle

No single indicator captures the interaction between interest rates and economic expectations as cleanly as the yield curve, the spread between short-term and long-term government bond yields.

A normal, upward-sloping yield curve reflects a healthy economy: short rates are low (easy monetary policy), long rates are higher (the market expects growth and inflation over time). An inverted yield curve, where short rates exceed long rates, is the market's most reliable recession signal. It has preceded every US recession since 1955 without a single false positive that led to a recession within two years.

Why does inversion predict recession? Because it reflects a specific set of conditions: the central bank has raised short rates aggressively enough to cool the economy, and the bond market has responded by pricing in future rate cuts. The financial system is being squeezed, as banks borrow short and lend long, and when the curve inverts, their net interest margin collapses. Credit tightens. Investment falls. Recession follows.

For asset allocation, the shape of the yield curve is arguably the single most important macro signal available. A steepening curve from a low base (early cycle) is the green light for risk assets. A flattening or inverting curve (late cycle) is the signal to reduce cyclical exposure and rotate toward defensives, long bonds, and quality.

Putting It Together: Where We Are Now

The rate cycle that began in 2022 was the most aggressive tightening since Volcker. The Fed raised rates from zero to over 5% in fourteen months. The effects were felt across every asset class in precisely the ways this framework would predict: bonds fell sharply, high-duration tech suffered, defensive sectors outperformed, and gold recovered its real-rate sensitivity.

The cuts that began in late 2024 continued through the autumn of 2025, with the Fed cutting three times in the final quarter of the year, bringing the federal funds rate to 3.5%–3.75%. For a brief window, it looked like a textbook early-cycle rotation was underway: credit conditions were loosening, the yield curve was steepening, and rate-sensitive sectors were beginning to outperform.

Then the Iranian conflict changed the calculus. Oil prices surged more than 40% in March 2026. Core PCE, which had been grinding toward 2%, is now projected at 2.7% for the year. The Fed paused at both its January and March 2026 meetings. The cutting cycle is on hold, and the dot plot, which still shows one cut in 2026, is more contested internally than at any point in the current cycle. Three FOMC members dissented against the December 2025 cut; several have since flagged the possibility that the next move could be a hike if inflation reaccelerates.

This is the texture of the current moment: a cycle that looked like it was turning, interrupted by a geopolitical shock that has reinjected uncertainty into every asset allocation decision. The rotation playbook is not wrong. It is just paused. Energy and defensives are repricing in response to the oil shock. Long-duration bonds are repricing lower as the market absorbs the inflation risk premium. Gold, paradoxically, is performing well, driven not just by the real rate framework but by central bank demand from non-Western institutions reducing dollar exposure.

I do not think anyone can call the next twelve months with confidence. But understanding the framework, including the history of interest, the mechanics of the discount rate and the sector rotation clock, is what allows you to form a view and update it systematically as the evidence comes in. The map is not the territory. But without the map, you are simply reacting to noise.

This is the second article in an ongoing series on the foundations of macro finance. The first article, Money is Debt, traced the history of money from barter to the fiat system. Future articles will cover the history of inflation, the mechanics of central bank balance sheets, and the logic of Net Fed Liquidity.