The reason why public financial institutions that should tightly regulated have great power and oppress the private sector, which has been significantly deregulated in recent years, is often thought to be that so many privileges are given to public financial institutions as government enterprises. Indeed, we agree that government enterprises have had privileges, but if total size of them is smaller than that of their restrictions as government enterprises, it is difficult to say that they are the main cause of competitive dominance of government enterprises. Nishigaki (2009a) re−estimated sizes of privileges given to Japanese Postal Savings in the 10 years before privatization (1997FY-2006FY), and found that the size as to the accumulated amount of the 10 years was considerably smaller than that in the method of Japanese Bankers Association (2002, 2004), to which Yamori and Nishigaki (2004) had pointed its irrationality and great possibility of overvaluation. This paper firstly estimates sizes of restrictions (such as universal service obligations, social contribution activities, and opportunity costs caused by regulations of investments and businesses) given to Japanese Postal Savings in the same term, and secondly compares the total size with that of privileges in time−series. We will find the facts that, in the first half of the period, the privileges and the restrictions were almost balanced, so that in this regard no evidence can be confirmed that Postal Savings should have been oppressing private banks in Japan, and in the latter half (age of Japan Post), the balance came to be collapsed because of the large reduction of the privileges and of the rapid increase of the opportunity costs, as a result, its social contribution activities had to be reduced sharply.