Five of GMC's ten nearest neighbors by audience shape are restaurants, beverages, or discount retail — not other vehicle brands. Similarity here measures how closely two entities' audiences resemble each other in composition; a score of 0.90 means the audiences look nearly identical in structure, regardless of what the entities sell.

The shape is broad, with scores running from 0.90 down to 0.80 across all ten neighbors and no single dominant pull. Dodge (social) leads at 0.91, followed by Parts & Accessories at 0.86 and Chevrolet (social) at 0.85 — three Auto subcategory neighbors that form the automotive core of the cluster. Ford Mustang adds a fourth at 0.83, and O'Reilly Auto Parts rounds out the automotive-adjacent group at 0.82. But sitting at nearly the same similarity level are Dairy Queen at 0.83, McDonald's at 0.80, Subway (social) at 0.80, Mountain Dew at 0.80, and Discount Stores at 0.80. The restaurant and value-retail neighbors aren't outliers — they're statistically indistinguishable from the auto-parts neighbors in terms of audience overlap.

The pattern points to an audience that is simultaneously mainstream across automotive and mass-market consumer categories, with no sharp boundary between the two.