Market Cap Weighted

Also seen as: Market Cap, cap weighted, capitalization weighting

Fincanva describes how this method behaves; it never recommends an allocation method or tells you which weighting to run. Fincanva provides no financial advice — see Is this financial advice?.

How is a market-cap weight calculated?

Each instrument's weight is its own market capitalization divided by the total market capitalization of all the instruments being allocated across.

where the numerator is instrument $i$'s own market capitalization, the denominator is the sum of the capitalizations of all $N$ instruments in the allocation, and $w_i$ is the resulting weight. Because the weights are shares of a total, they always add up to the whole capital being allocated.

What counts as a good value?

There is nothing to configure, so what matters is the shape of the result: cap weighting concentrates capital in the largest holdings. A handful of very large companies can absorb most of the allocation while the rest of the list receives a fraction of a percent each, which means the strategy's outcome is driven mostly by those few names. That is a property of the method, not a fault — but it is why a cap-weighted allocation and an equally weighted one over the same instruments can behave very differently. Read the result alongside a concentration check, such as how much of the capital the top few weights hold.

Defaults in Fincanva

• Market Cap Weighted has no parameters: the weights follow each instrument's market capitalization, so there is nothing to set.
• It is available only inside a strategy, across its instruments. It is not one of the six methods a Combined can use to split capital across its member strategies.
• It does not use the In-sample calculation window: it reads current capitalizations rather than a window of history.
• Weights are recomputed at each rebalance date, so as companies grow or shrink relative to each other their shares move with them.

Worked example

A strategy holds two stocks. One has a market capitalization of $500 billion; the other, $50 billion — a 10:1 ratio. The total is $550 billion, so the weights are 500 ÷ 550 = 90.9% and 50 ÷ 550 = 9.1%. On $100,000 of strategy capital that is about $90,900 in the large company and $9,100 in the small one.

Compare that with Equal Weights over the same two stocks, which would put $50,000 in each. If the small company then doubles while the large one is flat, the equally weighted version gains roughly 50% and the cap-weighted version roughly 9% — the same two instruments, the same period, a different allocation method.