World War II devastated pupil numbers, but IMZ kept going. In 1945, Dr Husmann was involved in Operation Sunrise, the secret negotiations that led to the surrender of the German Army in northern Italy. He handed the directorship of the school to Dr Josef Ostermayer in 1946, but maintained in close contact and set up the Max Husmann Foundation to ensure the continuation of the principles on which he founded Institut Montana Zugerberg.