Between 1946 and 1961, the United States distributed over 25 billion U.S. dollars to Asian countries in the form of loans or grants. 17 billion was given in the form of economic assistance, while 8.3 billion was given as military assistance. Of this 25 billion billion, almost 19 billion came during the period between 1953 and 1961, as Asia became the focal point of the U.S.' efforts to contain the spread of communism across the globe. Apart from Japan (occupied by the U.S. following WWII) and the Philippines (became independent from the U.S. in 1946) all other countries received the majority of their loans and grants in the Mutual Security Act period.
Korea
The largest sum, totaling at over five billion dollars (3.2 billion in economic assistance and 1.8 billion in military assistance), was paid to South Korea. The U.S. has had a permanent presence on the peninsula since the Second World War, and made up the bulk of the UN's forces during the Korean War (1950-1953). Following the war, the U.S. maintained a military presence in South Korea due to the perceived threat of North Korea, an as an additional power base in East Asia.
Taiwan
The second largest sum was paid to Taiwan. Between the Second World War and 1979, the United States was politically aligned with and financially supported the government in Taiwan. During this time the U.S. had a military presence on the island and officially recognized the Taiwanese government as the official government of China. Taiwan became strategically important during the Korean War, during which the U.S. increased its military presence and investment in the island, in fear of an invasion from the mainland by the People's Republic of China. Following the Sino-Soviet split in the 1960s, the U.S. gradually improved its relationship with the government the People's Republic of China; in 1979, the U.S. changed its stance and officially recognized the Chinese government in Beijing as the legitimate government of China, and largely withdrew from Taiwan.