Conversion’s Stocks Tumble After Delisting : Wall Street: Amex says only that ‘they did not comply with our . . . disclosure policies.’

Stock of Pasadena-based Conversion Industries and several of its affiliated companies plummeted Wednesday after the American Stock Exchange said it plans to delist Conversion and its part-owned Beta Well Services.

The Amex, citing unspecified disclosure problems, halted trading in Conversion and in Beta on Tuesday, after making its delisting decision.

However, both stocks traded in the over-the-counter market Wednesday, where Conversion tumbled $1.19 to close at $1.38, and Beta plunged $4 to finish at $1.75.

An Amex spokeswoman in New York would not say why the exchange is seeking to delist the stocks other than that “they did not comply with our listing agreement and disclosure policies.”

Conversion, which owns 8.6% of Beta, declined to comment, although a spokesman said the firm will request an Amex hearing.

The Amex decision to jettison the stocks is a rarity, marking the first such move by the exchange since 1971. It casts another shadow over Conversion and Beta, both of which have stirred controversy.

Conversion, formed in 1983 as a Canadian energy firm, became a merchant banking operation in 1991. It purchases stakes in small companies, then helps take them public in stock offerings.

But Conversion has been under scrutiny for its ties to Tamaron Investments, a Colorado brokerage that has had run-ins with securities regulators. Conversion stock has tumbled from $33.25 in 1993.

Beta was formed in 1988 to provide oil field services. Its stock surged as high as $20 in 1993, in part on excitement over Russian projects the firm said it was developing. But the stock has plunged this year as revenue has dropped.

Shares of other Conversion spinoffs also fell Wednesday. On the Amex, North American Recycling slid 31 cents to $2, CVD Financial slumped 50 cents to $1.125 and Statordyne lost 19 cents to $1.31.