Bubble chart showing largest US startups defined as privately owned companies. Companies are plotted along two axes showing current revenue and total funding received so that the ranking is easily visible. No observable trend or correlation exists between both dimensions.
Uber has received exceptional funding. In order not to squeeze other bubbles together an axis break has been used for the x-axis.
A third dimension is added with bubble areas being proportional to the current company valuation. Though exact values are not easy to read, differences are made clear. Technically, a fourth dimension with discrete values is added by grouping bubbles by color. Companies that are headquartered outside the Silicon Valley receive a distinct color.