Private fare
Private fares or negotiated fares (also known as a consolidator, unpublished, or bulk fares) are prices for air seats that are not listed anywhere online, be it an airline website or OTA. Air consolidators get these concealed discounted fares from airlines, add a markup, and pass them on to retailers (travel agents).
Such fares can be part of a purposefully vague advertisement like “best prices” or “cheapest” tickets — without mentioning precise figures, sold as part of a package, or shared over the phone. Private fares offer the best savings on international flights, business/first-class seats, last-minute purchases, and one-way tickets. However, their trade-offs include high cancellation penalties, issues with loyalty programs, and a number of restrictions (e.g., such tickets are often nonrefundable, non-exchangeable, etc.).