The new economics of capital

Four forces lifting the long end

Long-term interest rates ultimately reflect the balance between savings and investment. For much of the past two decades, that balance favored persistently low yields. Today, four structural forces are reshaping that equilibrium. 

The first is greater sovereign borrowing. Governments are financing substantially larger deficits than they were before the pandemic. In the US, the stock of Treasury securities held by the public has expanded from roughly $4.5 trillion in 2007 to more than $31 trillion today, while debt held by the public has risen from around 35% of GDP to about 101% of GDP. Annual federal net interest payments now exceed $1 trillion, while borrowing requirements are likely to remain elevated as governments finance defense, industrial policy, energy security and age-related spending. 

At the same time, the growing supply of sovereign debt must increasingly be absorbed by private investors. Central bank balance-sheet expansion is no longer providing the same degree of support to duration markets that characterized much of the previous decade.

The second force is stronger private demand for capital. Artificial intelligence is driving one of the largest investment cycles in decades. The five largest US hyperscalers are expected to spend as much as $800 billion on capital investment this year, with much of that spending directed toward AI infrastructure and computing capacity. Digital infrastructure, manufacturing reshoring, the energy transition and higher defense spending are also lifting capital demand. These forces may support productivity over time, but they require substantial financing today. 

The third force is inflation volatility. Inflation expectations remain broadly anchored, but the inflation process has become less predictable. Trade policy, geopolitics, energy markets, demographics and supply-chain resilience are recurring sources of price pressure. The recent oil-price shock is a reminder that supply shocks can quickly complicate the policy outlook even when underlying inflation is moderating. In this environment, investors require more compensation for committing capital over longer horizons. 

The fourth force is policy credibility. Central bank independence, fiscal dominance risks and the credibility of inflation-targeting frameworks now matter more than they did when inflation was persistently below target. In an environment of higher debt burdens, larger fiscal deficits and more frequent supply shocks, investors place greater weight on policymakers' ability to preserve price stability over time. Greater uncertainty about the inflation outlook or the future policy path raises the compensation investors require to hold long-term debt. 

Why this matters for business leaders

Long-term interest rates influence far more than government borrowing costs. They shape mortgage rates, corporate financing costs, commercial real estate valuations, acquisition activity, pension liabilities and the discount rates used to evaluate investment opportunities.

For corporates, the interaction between risk-free rates and credit spreads is critical. Higher Treasury yields lift the baseline cost of financing. Credit spreads remain historically tight, cushioning some of that increase, but the scope for further compression appears limited. A deterioration in risk appetite or increase in default concerns could widen spreads and intensify refinancing pressures, particularly for highly leveraged borrowers and sponsor-backed companies.

That divergence is already visible in the resilience of AI-related investment alongside weaker activity in more interest-rate-sensitive sectors, including commercial real estate and parts of private equity.

The persistence of a higher and more volatile cost of capital poses the greatest concern. With long-term yields at a higher baseline, geopolitical or policy shocks have greater scope to push financing costs higher, crowd out private investment, weigh on consumer spending and tighten financial conditions.

As more cash flow is absorbed by debt service, prospective buyers can sustain less leverage and are likely to offer lower prices. That can widen the valuation gap between buyers and sellers, slowing exits and leaving capital tied up in older private-equity funds. Lower distributions can also limit investors’ capacity to commit capital to new funds.

For business leaders, the capital playbook needs to reflect this adjustment. Cost-of-capital assumptions should be refreshed and hurdle rates stress-tested. Debt maturity walls deserve closer scrutiny, while fixed-vs.-floating exposure should be reassessed. Liquidity buffers matter more. Capital should be directed toward investments with clearer productivity gains, stronger cash-flow visibility and more resilient returns.

The defining feature of the post-financial crisis expansion was an abundance of inexpensive long-term capital. The new economics of capital are being shaped by larger fiscal deficits, stronger investment demand, greater inflation volatility and heightened sensitivity to policy credibility. For business leaders, the challenge is no longer simply forecasting the next move by the Federal Reserve. It is ensuring that strategies, balance sheets and capital-allocation frameworks reflect a world in which capital remains available but is no longer abundant or inexpensive.