# Customer-logo sections that show a Y Combinator company

Homepages on four lists (Y Combinator, Inc 5000 2026, a B2B SaaS list, unicorns),
checked for a customer-logo section and for Y Combinator companies among the logos.
Homepage only, one page per company, one crawl in September 2026. Each domain is counted once.

Cite: Installmap Research, "The great startup circle jerk: 1 in 3 new YC logo walls shows another YC startup", installmap.com, 2026-09-27, https://installmap.com/research/yc-startups-sell-to-each-other

## Files

- `by_list.csv` - one row per list.
  - `list` YC, Inc, SaaS or Unicorns.
  - `homepages` homepages read.
  - `logo_walls` homepages with a customer-logo section.
  - `walls_with_yc_company` logo sections showing at least one YC company other than the page's own.
  - `share_pct` = walls_with_yc_company / logo_walls, in percent.
  - `walls_with_non_household_yc_company` logo sections showing a YC company outside the 43 household names in METHOD.md.
  - `share_non_household_pct` = walls_with_non_household_yc_company / logo_walls, in percent.
  - `yc_logo_images` logo images matched to a YC company; `logo_images` all images inside the logo sections.
  - Counts under 5 print as `<5`.
- `yc_by_batch_block.csv` - YC logo sections by block of batch years (2012-2017, 2018-2021, 2022-2024, 2025-2026).
  - `batch_years`, `logo_walls`, `walls_with_yc_company`, `share_pct`, `walls_with_non_household_yc_company`, `share_non_household_pct`.
- `walls.csv` - one row per homepage, on any of the four lists, whose logo section shows at least one YC company.
  - `list`, `domain`, `company`, `batch` (YC batch, blank for other lists).
  - `yc_companies_shown` the YC companies matched, separated by `|`.
  - `non_household_shown` the same, minus the 43 household names.
- `most_shown.csv` - YC companies ranked by the number of YC logo sections showing them.
  - `company`, `batch`, `domain`, `walls_showing_it`.
- `METHOD.md` - cue phrases, window, name-matching rules, the household list, the funnel and the limits.

Shares are of logo sections, not of all homepages. A logo without matching alt text is missed, and a logo whose alt text equals a YC name is counted even when it is another company; in a hand check of 40 walls, 31 were clear customer walls.

License: CC BY 4.0. Credit "Installmap" with a link to the report.