1936
Marsman business ventures had grown and diversified into other fields -- engineering, insurance, air transportation, machinery, hardware, pharmaceuticals and foodstuffs. Due to these expansion activities and the growing involvement in the trading business, the organization's headquarters were moved from Baguio to Port Area, Manila. The Marsman Building in Intramuros was built to accommodate the growing work force that manned the Marsmans' various business interests. During the Japanese Occupation, the building was used as the headquarters of the Japanese Navy. After the war, the Company resumed its operations at a new location in Intramuros. The original Marsman Building still stands today and is presently owned by the Philippine government.

1939
By 1941, the Marsmans had built one of the top business organizations in the Philippines. Its construction projects included the Nielsen Tower in the Manila Airport, one of the first airports in the country where they operated the Philippine Air Taxi Company (PATCO). This air transport service offered regular trips from Manila to Baguio as well as chartered flights to various destinations in the country.

The Soriano family later became involved in PATCO, which they later took over and developed into what is now Philippine Airlines. The original airport runway is now known as Paseo de Roxas in the heart of Makati's bustling business district while Nielsen Tower now houses the Filipinas Heritage Library where various cultural and literary events regularly take place.

1941
The Japanese Imperial Army occupies most of the Asian region, prompting many American and European-owned businesses to relocate their operations. At this time, Marsman and Company acquired Pacific Commercial Company (PCC), the largest trading company in the Philippines. Despite the imminent outbreak of war, the Marsmans continued the distribution of various products including office equipment, foodstuffs, farming equipment, hardware, heavy equipment and pharmaceuticals, demonstrating their commitment to the Philippines.

1945
The Second World War devastated the Marsman enterprises, which suffered losses and damages in excess of US$50 million. Not to be daunted, the Marsmans began to rebuild from the ruins after the war with the reactivation of five gold mines and the trading business. Marsman and Company represented all the major companies with interests in food, pharmaceuticals and construction.

After the Japanese army retreated, the first shipments of flour and milk into a war-ravaged Philippines were financed by the Marsmans using their personal funds and credit to bring food to starving Filipinos. Construction and engineering departments were likewise reactivated to help in the task of reconstruction. Among their accomplishments were the UP Engineering Building, the Ambuklao Hydroelectric project and the Nichols Air Base, now the domestic airport.

1948
Walter Dumermuth, a Swiss national, was hired by Marsman and Company in 1948 to develop the company's pharmaceutical distribution. All the various businesses were undergoing expansion at this point, with Pharmaceuticals aggressively promoted by Dumermuth.