Secret Swiss bank accounts are being used to manipulate U.S. commodity and stock markets, creating sensitive international regulatory problems that are likely to get worse as foreign investment in this country increases.

Secret Swiss accounts are implicated in suspected illegal insider stock and options trading in conjunction with several recent corporate takeovers, including the purchase of St. Joe Minerals Corp. by Joseph E. Seagram & Sons, the planned takeover of Santa Fe International Corp. by Kuwait Petroleum Corp. and the purchase of Amax Inc. by Standard Oil Co. of California.

The Securities and Exchange Commission has successfully sued one Swiss financial institution, Banca Della Svizzera Italiana, and has frozen profits allegedly made on the basis of insider information about the takeover of St. Joe Minerals.

Another, Banque Populaire Suisse, this week was banned from trading on U.S. commodity markets for three months for refusing to provide information about its activities in silver futures to the Commodity Futures Trading Commission. The CFTC also went to court this week seeking sanctions against a British coffee trader in a similar case.

Both the CFTC and SEC are pursuing other enforcement actions involving foreign traders, but so far federal regulators have found no way to rip down the veil of secrecy shielding Swiss bank records.

The legal actions have been aimed at the Swiss banks themselves, but it is the banks' customers that regulators are worried about. Although the buzzwords for the problem at the SEC and CFTC are "foreign traders," there is strong suspicion that American investors are using the Swiss banks as fronts.

The son of an executive of an American firm involved in one recent takeover is suspected of using foreign brokers to profit illegally from advance inside information about the deal. He allegedly opened an overseas investment account, then ordered the firm to buy stock in the U.S. company for him.

Once a U.S. citizen gets a numbered Swiss account, the same protections that keep secret the bank records of Swiss citizens apply to the account of the American customer.

Reluctant to be labeled as bankers for bad guys, Swiss authorities have cooperated quietly with U.S. regulators in some cases, but they are not about to abandon their bank privacy principals. Nor is any new international treaty likely to solve the problem, SEC member John Evans told a congressional subcommittee on Tuesday.

Evans testified before the House Commerce, Consumer and Monetary Affairs panel that is probing the impact of foreign purchases of U.S. business.

At the same hearing, officials of the Pacific Stock Exchange said they have uncovered information that a Swiss bank and the Kuwait offices of some U.S. investment firms were involved in illegal insider trading in Santa Fe options.

PSE President James Gallagher declined to name the bank, but said it placed orders for 1,000 Santa Fe options -- each for 100 shares -- and stood to make millions of dollars when the price of the stock jumped from $24 to $51 after the Kuwait takeover was announced.

Virtually the same thing happened in the St. Joe Minerals case, testimony by the SEC's Evans pointed out. The day before the takeover was announced, Banca Della Svizzera Italiana bought 1,000 options on St. Joe. The day after the takeover, the bank sold the options for a profit of $15 a share -- better than $1 million in two days.

Evans said the SEC's efforts to investigate illegal use of inside information "are often frustrated by an inability to obtain information from foreign institutions."

"We have tried all conceivable legal and diplomatic techniques and channels," the SEC member added. "But the delicate problems of international law and diplomacy that are involved . . . leave open the question of whether we will succeed."

SEC officials say they have found the Swiss authorities cooperative, but the CFTC's bid for records of Banque Populaire Suisse produced a protest to the U.S. State Department from the Swiss embassy. The folks from Foggy Bottom warned the CFTC to cool it.

The CFTC never did find out who Banque Populaire was buying silver for, making it impossible for investigators to link the Swiss bank to the Texas Hunts and Middle Eastern investors who were bidding up the price of silver. If there was a conspiracy to corner the silver market, it will be difficult to prove without knowing who the Swiss bank's customers were.

Commodity regulators, however, for the first time established their legal authority to punish foreigners for failing to provide information.

Kicking Banque Populaire out of U.S. markets for three months still didn't produce the facts the CFTC wanted. Some people in the agency suggest a subpoena enforcement action might have been more effective: Tell the Swiss to provide information or be held in contempt -- and be suspended from trading -- until you do.

The SEC also is encouraged by its success in freezing the profits of illegal trading through foreign accounts.