Yellow Bus Line (YBL), then a sole proprietorship owned and operated by Mr. Antonio C. Yap, was granted a certificate of public Utility Buses for the transport of passengers and freight for six (6) units servicing the routes from Marbel to Cagayan de Oro and vice versa.
At the start of its operations in 1958, the YBL had only three (3) buses and had to compete with several bus operators in the same area such as: Mindanao Bus Company, the Rojas Transportation and Bayoneta Transporatations in Marbel and other bus companies in Davao City. Mr. Antonio C. Yap, however, realized that operating in these areas with poor road conditions and dilapidated bridges, was not feasible. This prompted him to request from PSC a change to a shorter route Marbel to Dadiangas. Said request for amendment of route was approved in 1964 using 6 units’ regular buses and 1 reserve bus.
In April 1971, YBL opened the Tacurong to General Santos route via Tantangan and Isulan. Every year thereafter, more units were fielded in its authorized lines. As of December 1975, YBL had 32 units in operation. Inspite of the presence of new competitors such as La Suerte Bus Co., Tupi Liner and Mindanao Transway Express, Inc., YBL maintained its good service and schedules of trips for the convenience of the riding public.
On December 10, 1976, YBL was incorporated with authorized capitalization of P 4 million. The newly created corporation was named Yellow Bus Line, Incorporated (YBLI) and started its commercial operation in January 1977 with 32 buses.
YBLI concentrated its operation within the provinces of Sultan Kudarat and South Cotabato. Due to the presence of three (3) strong competitors (Surigao Bus Line, Bachelor Express and Villarecar Bus) operating along Marbel-Davao City, YBLI initially hesitated to venture in this longer route.
Finally in 1978, YBLI operated along the route of Koronadal to Davao City via General Santos City and Malungon and offered the