One word, different arrangements
In a securities margin account, borrowing may help finance a purchase of assets. In futures, margin commonly supports performance of a contract and changes in value are handled through clearing arrangements. Other derivatives have their own collateral methods. Although each uses the word margin, the legal relationship, cash flows and calculation rules are not identical. Start with the product's structure instead of assuming a percentage from one asset class applies to another.
Compare the economic exposure
For each position, identify quantity, price, multiplier, settlement currency and the amount of collateral required. Then examine how a plausible price change affects the full exposure. A low requirement can permit a large position without making it safer. Asset classes can also differ in liquidity, trading sessions and gap behavior, so comparing only the initial cash needed can hide the more important differences in potential loss and cash demands.
Consider combined positions carefully
A portfolio may contain positions that appear to offset each other, but a provider's margin calculation may recognize that relationship differently or not at all. Correlations can also weaken when conditions change. Read any netting or offset rules rather than assuming they match an economic intuition. FYLU has not confirmed cross-asset margin, portfolio offsets or live account terms; its educational pages cannot determine the collateral needed for a proposed combination of instruments.