A study panel in the Ministry of Economy, Trade and Industry is considering allowing listed companies to use special shares to ward off hostile takeovers.

But under such a system, companies would have the onus of disclosing information on their defensive measures, the panel said in a report released Wednesday.

Defensive measures envisioned by the panel include the use of shares that limit a takeover bidder's voting rights, or "golden shares," which give their holders veto power over acquisition proposals.

In addition to the disclosure of defensive measures, the panel is considering requiring companies to set a rule allowing shareholders to decide at general meetings to nullify the defensive measures.

Among other issues under study is a proposal that a listed company should be delisted if it keeps undue defensive measures over a set period of time.

A variety of measures to protect companies from unfriendly takeover attempts will be permitted under a new law to be enacted in May.

Later this month, the Tokyo Stock Exchange will release a draft policy defining proper defensive measures.

The METI study panel hopes its proposals will be taken into account in the TSE policy.

Under the law taking effect in May, listed companies will be able to use a wider variety of defenses against hostile takeover bids.

But the panel is worried the TSE may judge some measures as inappropriate and delist the companies that use them.