Companies cut their cross-shareholdings of allied firms to the lowest level in at least 19 years as banks stepped up selloffs ahead of stricter global requirements for capitalization.

Stocks held among corporate allies fell to 4.9 percent of the nation's total outstanding shares in the year that ended March 31, a two-point drop from the previous year and the lowest since Daiwa Securities Group Inc. started monitoring the data in 1991, a report by the company's research unit found.

"Cross-shareholdings held by banks are based on relationships with clients, so it doesn't mean that the shares they hold are ones that are likely to grow," said Keisuke Nitta, a strategist at NLI Research Institute. "A lot of the superior shares have already been sold off. It means a lot of unattractive stocks are still on their books."