At least three of the 10 Wall Street banks that were part of April's $1.4 billion settlement over alleged biased stock research have blocked analysts worldwide from trying to win investment banking business.

Citigroup Inc., the world's No. 1 financial services company and Goldman Sachs Group Inc. and Morgan Stanley, two large Wall Street investment banks, said they extended the ban to non-US countries.

Citigroup said it tightened its rules worldwide for research analysts about five months ago. Goldman Sachs said it did so in April and Morgan Stanley in June.

"Others will be pressed to follow," said Larry Soderquist, a professor at Vanderbilt University Law School in Nashville, Tennessee, and director of its Corporate and Securities Law Institute. "With the increasing global nature of the economy, it makes sense to have the same rules apply across the globe."

Citigroup's announcement came a week after Judge William Pauley of the US District Court in Manhattan, who is overseeing the settlement, but has yet to approve it, asked banks for more information on whether the ban on analyst conflicts applies to non-US affiliates or units.

The April 28 settlement among the banks, the US Securities and Exchange Commission, the NASD, the New York Stock Exchange, New York Attorney General Eliot Spitzer and state securities regulators ended some investigations into whether analysts slanted research to win banking business.

Susan Thomson, spokeswoman for Citigroup's Smith Barney unit, said: "Globally, we have adopted a policy that precludes analysts from attending investment-banking pitches. In the US there are no exceptions. Outside the US, our independent research management would only consider an exception when a foreign government asks specifically."

Mr Soderquist said: "Once one bank does it, others will likely be asked, if not forced, to do it by large institutional shareholders, the SEC or the judge."

The SEC and Judge Pauley declined to comment. SPLIT As part of the research settlement, Citigroup agreed to pay $400 million, more than any other bank.

It split its investment banking business from its research and retail brokerage units last year. It hired former Sanford Bernstein Chief Executive Sallie Krawcheck to run the latter, now known as Smith Barney.

Goldman Sachs spokesman Ed Canaday said: "We are applying the new rules globally, except where local listing rules or accepted market practice dictate otherwise."

Morgan Stanley spokeswoman Diana Quintero said her firm "globally prohibited its analysts from going on roadshows and pitches. Any exceptions or modifications would require the approval of (Morgan Stanley) law and compliance, as well as senior management."

Other banks involved in the settlement have not confirmed their plans for analysts. J.P. Morgan Chase & Co., Lehman Brothers Holdings Inc., Merrill Lynch & Co. and US Bancorp declined to comment. Bear Stearns Cos. and Credit Suisse Group Inc. did not immediately return calls seeking comment.

Paul Marrone, a spokesman for UBS AG's UBS Investment Bank, said the company "will evaluate situations on a case-by-case basis."

Separately, John Hoffmann, Citigroup's former global research head, has been notified by regulators - including the NASD, NYSE and SEC - that he may face civil charges over alleged misleading advertising, failure to supervise and unfair dealings with customers, said his lawyer, Charles Stillman of Stillman & Friedman PC.