It shows LOW 4.44% and HD 4.13%. But HD's MC is almost 3x of LOW. https://www.ishares.com/us/products/239512/ishares-us-home-construction-etf So the weight is not based on MC?
It's a float adjusted market cap, with further capping in the Select Speciality index series. The benchmark index it is following is Dow Jones U.S. Select Home Construction Index. The index is detailed here: https://www.spglobal.com/spdji/en/indices/equity/dow-jones-us-select-home-construction-index/ The methodology is here regarding select indices, capping etc. https://www.spglobal.com/spdji/en/d...methodology-dj-us-select-sector-specialty.pdf Float adjustment defined here: http://us.spindices.com/documents/index-policies/methodology-sp-float-adjustment.pdf
Years ago, HD's weight in ITB was closer to LOW's, but HD stock price has grown much faster, so HD's weight also has grown faster.