Quick answer: two correlated positions are not two trades, they are one trade at double size. Buying US30 and NAS100 with 1% risk each is, in practice, close to risking 2% on a single idea. The working rule: treat instruments that move together as one position and split the risk between them.
Key takeaways
- Correlation is not fixed; it shifts with the macro backdrop and the session.
- The two US indices usually move in the same direction, with different intensity.
- Gold and the dollar tend to move opposite each other — but not always.
- The risk that matters is the open portfolio's, not each individual order's.
What moves with what
| Pair | Usual relationship | What it means for your risk |
|---|---|---|
| US30 and NAS100 | Same direction most of the time | Two longs = nearly double the exposure |
| Gold and the dollar (DXY) | Frequently opposite | Long Gold plus short dollar is the same bet twice |
| BTCUSD and NAS100 | Sometimes together, sometimes not | Check this month's behaviour before assuming it |
| Gold and indices | Unstable, depends on what is driving the move | Not a reliable automatic hedge |
These are observed tendencies, not laws. On heavy macro days, almost everything can move as one block.
The calculation almost nobody runs
Take a $10,000 account risking 1% ($100) per trade.
| Open positions | Stated risk | Real risk if they move together |
|---|---|---|
| Long US30 | $100 | $100 |
| Long US30 + long NAS100 | $200 | close to $200 on one idea |
| Long US30 + NAS100 + BTC | $300 | up to $300 when risk appetite drives the day |
| Long Gold + short dollar | $200 | close to $200 on the same bet |
Three practical rules
- Group by idea, not by symbol. If two positions win and lose together, they are one.
- Split the risk inside the group. Want both US30 and NAS100? Use 0.5% each instead of 1%.
- Cap exposure per group. For example, never more than 2% in “equity risk” and never more than 2% in “dollar risk”.
How to check it in five minutes
- Overlay both charts in one window and compare the last 20 days.
- Mark three high-impact days and see whether they reacted the same way.
- If your platform allows it, add a correlation indicator and read the last month.
- Repeat monthly: what moves together today can separate tomorrow.
Portfolio risk, not order risk
When signals come from one system across several instruments, decide in advance how many simultaneous positions you accept. In Cortex Automation you choose which instruments stay active and at what risk, so you can cap the overlap before it happens; the Cortex Signal Kit covers US30, NAS100, Gold and BTCUSD, which is exactly the group where correlation needs watching. The sizing side is in the free ebook From the First Lot to Consistent Growth.
Frequently asked questions
What is correlation in trading?
A measure of how much two instruments move in the same direction. Positive means they rise and fall together; negative means they move opposite.
Can I hedge by buying Gold and selling indices?
Not reliably. That relationship changes with what is driving the move, so you can lose on both legs.
How many simultaneous positions are reasonable?
For a retail account, two or three uncorrelated ones is usually plenty. More positions almost always means more exposure to the same factor.
Does correlation change during the day?
Yes. Around the New York open the indices move almost in lockstep; in quiet hours each instrument follows its own liquidity.
Does correlation affect an automated system?
Significantly. If the system opens signals on several instruments at once, total risk can multiply even when each order is small.
Control exposure, not just entries. With Cortex Automation you choose instruments, risk and schedule; try it for five days with the Automation Test.
Disclaimer: educational content. The relationships described are observed tendencies and can change. Cortex Next is not a financial service and guarantees no results. Trading involves risk of loss.
