What moves indices: interest rates, earnings and the US dollar

An index is a basket of companies, so in the long run it follows what those companies earn. Day to day, though, three forces usually explain most of its moves: interest rates, earnings and the US dollar. Knowing how each one works helps explain why the same headline can lift one index and weigh on another.

A simple way to think about an index's level

Analysts often describe an index's level as two numbers multiplied together: what its companies earn, and how much investors are willing to pay for each dollar of those earnings (the valuation multiple, or P/E).

Illustrative calculation, not an expectation of results. Rates mostly act on the multiple; earnings act on the first number; the dollar touches both.

1. Interest rates

When rates and bond yields rise, future profits are worth less in today's money and bonds become a more attractive alternative. That usually lowers the multiple investors pay, and it often hits growth-heavy indices hardest, because more of their value sits in profits expected far in the future. That is one reason the Nasdaq 100 often reacts more strongly to rate news than the Dow.

The Federal Reserve holds eight scheduled meetings a year. Decisions come at 14:00 New York time, 23:00 in the UAE in US winter, followed by a press conference half an hour later. Inflation (CPI) and jobs (NFP) data at 08:30 New York time, 17:30 UAE in winter, move expectations for those meetings and often move indices before the open.

2. Earnings

Four times a year, companies report what they actually earned and what they expect next. Results above or below expectations can move a stock sharply, and when the largest members of an index report in the same week, the index can move with them. Guidance, the outlook for coming quarters, often matters as much as the quarter itself. The practical side of results days is covered in earnings season and gaps.

3. The US dollar

Many large US companies earn a big share of their revenue abroad. When the dollar strengthens, those foreign sales are worth fewer dollars once converted, which can weigh on reported earnings. A sharply stronger dollar can also tighten financial conditions globally. The relationship is not fixed: in some periods the dollar and US indices rise together, especially when money flows into US assets. It is a factor to watch, not a rule.

Other forces worth knowing

• Oil: higher crude prices tend to help energy companies and can hurt airlines and consumers; very high oil can feed inflation and, through it, rate expectations. See WTI vs Brent.
• Risk sentiment: geopolitical shocks or banking stress can make investors sell risky assets together, whatever the earnings picture.
• Index composition: a technology-heavy index and a price-weighted 30-stock index can react differently to the same news.

Turning drivers into a plan

None of these drivers gives an entry condition by itself. What they give a plan is context: which days carry scheduled risk, which times to mark, and when a smaller size or no trade at all might be part of the rules. The market sessions tool helps place each release in Gulf time, and the risk-reward calculator checks whether a planned trade still makes sense once the stop is placed around that risk.

In short

Indices follow earnings over time and the multiple investors pay for them, and that multiple is very sensitive to rates. The dollar, oil and risk sentiment add to the picture. A written plan marks when these forces are scheduled to arrive, in Gulf time, before the session starts.