22. Beta-Weighting

Position Delta: Deltas of the same underlying can be added up to get total exposure
Portfolio Delta: Deltas of different underlying's can not be added up to get total exposure

One way to get the portfolio delta is to standardize the deltas of all your different underlying's so they all refer to a single reference underlying and then a portfolio delta with respect to that reference can be obtained as an approximation for total direct portfolio exposure

We call Beta as a measure of a stock or a portfolio volatility with respect to the general market.
Beta Weighting is standardizing the deltas of a whole portfolio to a reference instrument using their prices and beta coeficients.. The reference is usually the S&P500 Index.

It represents the profit/loss we would get as the beta-weighting instrument goes higher by 1$ (for every $1 the SPY goes how much does my portfolio go up)

Beta-Weighed Delta = Delta * ( [Stock Price*Stock Beta] / [Ref. Price*Ref.Beta])

You don't need to know this formula since platforms already have beta-weighted values for all equities. You could beta-weight to something else, like the QQQ depending on your portfolio