Position weight

Weight is a position's share of the total:

weight = position value / total value of the portfolio

It is the column that turns a list of holdings into a picture of concentration. A portfolio can look diversified as a list of twenty names while one of them carries 60% of the money, and weight is what makes that obvious.

It follows your filter

Weight is calculated against whatever is currently in view. Filter to a single sector and the weights recalculate within that sector, so they still sum to 100%.

That is deliberate, and it is the behaviour you want when asking "how concentrated am I within my technology holdings". It does mean a weight read under a filter is not the same number as the same position's weight in the whole portfolio, so it is worth knowing which one you are looking at.

Weight drifts on its own

You do not have to trade for weights to change. A position that rises faster than the rest of the portfolio grows its own weight, which is how portfolios quietly become concentrated in whatever has done best.

This is the ordinary mechanism behind most concentration: not a decision, but the absence of one.

What Gylder does and does not do with it

The dashboard shows weight, and the diversification donut on the Overview tab is built from the same figures across the dimension you pick. Clicking a slice filters everything to it.

Gylder does not recommend a target weight, flag a position as overweight, or suggest rebalancing. Those are decisions that depend on your horizon, your tax position and what the rest of your net worth looks like, and a threshold applied without knowing any of that would be advice dressed up as a calculation.

The Analysis section separately surfaces concentration across your whole net worth rather than within investments, which is a different question and a useful complement.