A total of 145 companies across Japan have sought police protection for shareholder meetings to be held later this month in an apparent bid to thwart "sokaiya" corporate extortionists, the National Police Agency said Thursday.

The firms are among 154 companies that have scheduled shareholder meetings March 29, the NPA said, adding that 470 police officers will be assigned to the gatherings.

Shareholders' meetings in Japan generally attract corporate racketeers known as sokaiya, literally "shareholders' meeting specialists," who own shares of targeted firms and usually attempt to make their presence felt at shareholder meetings.

They often demand money in return for not disrupting the gatherings or divulging embarrassing corporate information.

According to the NPA, the number of sokaiya in Japan has remained steady over the past year at about 400.

The number of companies that noted sokaiya attending meetings last year fell by 58 from 1999 to 139 last year. The number of sokaiya attending also declined by 113 to 202, according to police statistics.

The number of sokaiya in Japan has continually declined since police began compiling the figures in 1991, when the racketeers were estimated at 1,300.

Police launched a major crackdown against them in 1997 after a number of major corporations were found to have had ties with sokaiya and paid them substantial sums.