TOKYO (Reuters) ― Japan’s Financial Services Minister Tadahiro Matsushita said on Tuesday he has asked 12 large securities houses involved in public offerings to check their information control systems and inform his ministry of the results.

The request comes after scandals over insider trading in number of large public offerings in Japan, including one involving employees of Nomura Securities.

Five Japanese and seven foreign firms were named by the ministry. Besides Nomura the Japanese firms are Daiwa, Nikko SMBC, Mizuho and Mitsubishi UFJ Morgan Stanley. The foreign houses named are the Japanese brokerage arms of JP Morgan, Deutsche, Goldman Sachs, Citi, UBS, Merrill Lynch and Morgan Stanley.

Since March, Japan’s Securities and Exchange Surveillance Commission has sought fines against three investment firms in a total of four cases brought so far in its probe into insider trading ahead of public share offerings, a near endemic problem in Japan.