A bubble chart displays the relationship between average salary and revenue per employee for 20 tech companies, with bubble size encoding employee count. Built with D3.js v7 and SVG, the visualization uses d3.scaleLinear for axes, d3.scaleSqrt for bubble radius, and d3.scaleOrdinal with schemeCategory10 for color coding. Hovering reveals a tooltip showing company name and employee count. Data comes from an external CSV file loaded via d3.csv.