Masaru Ibuka, who turned a local factory into internationally renowned Sony Corp., left an inheritance worth roughly 9.96 billion yen when he died in December, taxation authorities said Tuesday.

Four people, including his eldest son, Makoto -- who is a managing director at one of Sony's affiliates -- were heirs to his fortune, and the inheritance tax was estimated at over 5.1 billion yen.

The major portion of his inheritance was in the form of securities such as Sony shares, and included a condominium in Tokyo's Minato Ward as well as villas in the resort towns of Karuizawa, Nagano Prefecture, and Hakone, Kanagawa Prefecture, according to sources. The heirs paid all of the inheritance tax by submitting their Sony shares to authorities.

In October, Makoto Ibuka and another heir used their inheritance to set up a memorial scholarship fund worth 1 billion yen, and this was deducted from the tax amount.

In 1946, Ibuka and others, including Akio Morita, set up a small firm that became the predecessor of Sony. Four years later, the company became the first in Japan to sell tape recorders, and in 1955 offered Japan's first transistor radios.