The market in question: https://manifold.markets/sheep/will-the-majority-of-traders-hold-n

When the market 'Will the majority of traders hold "no" when this market closes' closes, this market will also resolve.

This will resolve "YES" if there is any single trader holding >= 500 shares (of either YES or NO) when the above market closes. If no such trader exists, this market will resolve "NO".