Interest Rates
Interest rates are the price of money: what borrowers pay lenders for its use over time. Equity investors meet them twice, first as a cost running through corporate income statements, then as the discount rate that converts a company’s future cash flows into a present value.
The second encounter is usually the expensive one.
The math
Value a stock as a growing stream: next year’s cash flow divided by the discount rate minus growth. A company generating $5 per share, growing 3 percent, discounted at 8 percent, is worth 5 / 0.05 = $100.
Move the discount rate to 10 percent and the same stream is worth 5 / 0.07, about $71. Nothing about the business changed, yet fair value fell 29 percent; a $50,000 position repriced this way is worth roughly $35,500.
| Rate at 8% | Rate at 10% | |
|---|---|---|
| Divisor (rate minus 3% growth) | 0.05 | 0.07 |
| Fair value ($5 cash flow) | $100 | about $71 |
| A $50,000 position | $50,000 | about $35,500 |
The further into the future a company’s cash flows sit, the harder this arithmetic bites, which is why speculative growth names swing hardest when rates move.
The trap
Forecasting. Positioning a portfolio around expected cuts or hikes puts an investor in competition with bond markets that reprice expectations continuously, and the track record of rate predictions, professional and amateur alike, is humbling.
The compounding error is owning leveraged companies whose thesis quietly requires cheap refinancing forever.
The move
Replace the forecast with a stress test. For each holding, check the debt maturity schedule, the fixed versus floating mix, and interest coverage recalculated at meaningfully higher rates.
Then demand a purchase price that works without generous rate assumptions. A stock picker cannot know where rates go next; a portfolio built to be indifferent to the answer does not need to, and that indifference is itself a durable edge over investors who trade every rate headline.
Reference: Federal Reserve, monetary policy