[1] The origins of SMBC Nikko Securities can be traced back to a company named Kawashimaya Shoten (川島屋商店) which was formed in July 1918 by Genichi Toyama.

[3] In April 2012, the Financial Services Agency fined the firm for leaking information about a stock offering which was considered insider trading.

[1][7] Directors of the firm passed on word of the offering to at least 21 sales branches without carrying out the proper internal procedures to control the information flow.

The deal was said to be a roughly 1 trillion yen ($12.4 billion) offering by Sumitomo Mitsui Financial Group, Nikko's parent, in early 2010.

[7] In November 2021, the Securities and Exchange Surveillance Commission (SESC) launched an investigation into the firm over suspicious stock transactions.