How the index is built

Who is in it

6,320 companies are in the public YC directory (fetched 2026-10-22, UTC). 4,369 are still active (or acquired but still running as their own site) and have a company website. Of those, 2,210 have at least 5K visits a month in the panel and are ranked, including Fall 2026, the latest full batch. 1,297 are below that floor, 800 have no panel data, 59 were left out because the domain could not be matched to the company name (or is a platform page), and 3 are listed under a batch that has not started yet.

Where traffic comes from

Monthly visits, average visit length, bounce rate and 12 month history come from traffic.cv, which reflects a browsing panel. They are estimates, strongest for large sites and noisy below about 50,000 visits. Data month: September 2026. Fetched 2026-10-22.

Attention minutes

Monthly visits times average visit seconds, divided by 60. It rewards sites people stay on. Mindshare is a company's attention minutes divided by the total of all companies in the index. The Top 100 is the first 100 by this number.

Movers

Change in monthly visits, September against June 2026. Only companies with at least 50K visits at both ends are ranked. A jump can come from a launch, a campaign, an outage, a viral post or bot traffic; the index does not say which.

Cautions

• Small sample. Under 50,000 visits a month.
• Spike. Latest month is more than 2.5 times the median of the previous six, on a site above 20,000 visits.
• Falling fast. Down 40% or more since June (50,000 visits or more in June).
• Short history. Fewer than six months of data.
• Very short visits. Under 20 seconds on a site above 100,000 visits: often a redirect, API or login site.

Cautions are rules, not opinions, and a caution is not a verdict on the company.

Industries and percentiles

Industry and category labels are YC's own. A percentile follows the industry rank: it is the share of ranked companies in the same industry that a company's attention minutes beat. Cohort lines use only companies with a full 12 months, indexed to October 2025, so no company enters or leaves mid line.

Brand searches (from DawnTrend)

Where a company's name was searched on Google (1,366 companies, monthly volumes for September 2025 to August 2026) we show the volume and its change, June to August against October to December. Volumes are bucketed by the provider and a name that is also an everyday word can inflate its count, so treat it as a sign, not a count. Source and date: DawnTrend brand-search collection (Google monthly search volume for the company name, bucketed), Sep 2025 to Aug 2026, collected 2026-09-30.

How this differs from DawnTrend

DawnTrend measures brand search interest and scores brands from 0 to 100 across the S&P 500, Nasdaq-100, Fortune 100 and YC. Mindspent measures what happens on the site (visits times visit length) for Y Combinator companies only, by batch and industry, with cautions and a watchlist. We borrow DawnTrend's search data as one extra lens; the traffic data and the rankings are our own.

Known limits

• Only the main domain is measured
• Panel estimates, rounded to three significant figures
• A company with several products on several domains is understated
• This is not investment advice and not affiliated with Y Combinator

Wrong match?

If a company is attached to the wrong domain, reply to any newsletter issue and it is removed or fixed in the next data month.