Keeping one's money very secretly is an old practice, for we find this practice present even during the reign of Maharaja Prthu
SB Canto 4
The reciters continued: No one will be able to understand the policies the King will follow. His activities will also be very confidential, and it will not be possible for anyone to know how he will make every activity successful. His treasury will always remain unknown to everyone. He will be the reservoir of unlimited glories and good qualities, and his position will be maintained and covered just as Varuṇa, the deity of the seas, is covered all around by water.
There is a predominating deity for all the material elements, and Varuṇa, or Pracetā, is the predominating deity of the seas and the oceans. From outward appearances the seas and oceans are devoid of life, but a person acquainted with the sea knows that within the water exist many varieties of life. The king of that underwater kingdom is Varuṇa. Just as no one can understand what is going on beneath the sea, no one could understand what policy King Pṛthu was following to make everything successful. Indeed, King Pṛthu's path of diplomacy was very grave. His success was made possible because he was a reservoir of unlimited glorified qualities.
The word upagupta-vittaḥ is very significant in this verse. It indicates that no one would know the extent of the riches King Pṛthu would confidentially keep. The idea is that not only the king but everyone should keep his hard-earned money confidentially and secretly so that in due course of time the money can be spent for good, practical purposes. In Kali-yuga, however, the king or government has no well-protected treasury, and the only means of circulation is currency notes made of paper. Thus in times of distress the government artificially inflates the currency by simply printing papers, and this artificially raises the price of commodities, and the general condition of the citizens becomes very precarious. Thus keeping one's money very secretly is an old practice, for we find this practice present even during the reign of Mahārāja Pṛthu. Just as the king has the right to keep his treasury confidential and secret, the people should also keep their individual earnings a secret. There is no fault in such dealings. The main point is that everyone should be trained in the system of varṇāśrama-dharma so that the money is spent only for good causes and nothing else.