Tokyo Sowa Bank dropped sharply on the Tokyo Stock Exchange Monday, reflecting investors' concerns over the financial institution's creditworthiness.

The shares plunged further on a news report that the Financial Supervisory Agency found the bank was in a capital deficit of 100 billion yen at the end of last September, which reduce its previously reported captial-to-asset ratio.

Tokyo Sowa shares closed at 75 yen, down 15 yen from Friday, after hitting a record low of 60 yen earlier in the day, at which point trading in the issue was temporarily halted.

Tokyo Sowa stock has been spiraling downward since May 14, when the Tokyo-based regional bank disclosed that its capital-to-asset ratio had fallen to 2.4 percent. It needed a figure of at least 4 percent for authorities to be satisfied with its performance. The FSA is now asking the bank to reassess its 1998 balance sheets.

According to market participants, many investors seem intent on securing profits by buying and selling the stock swiftly.