The eight-person jury seated in the civil fraud case of a former Pimco Equity Advisors executive heard their first testimony yesterday, as the Securities and Exchange Commission tried to prove Stephen Treadway was complicit in a client’s violations of company policy.

The SEC called a former Pimco vice president of operations, Steve Howell, and a former senior vice president of institutional marketing and client services, John Cashwell Jr., to try to prove that Mr. Treadway allowed Canary Capital Partners to violate Pimco’s rule against “market timing.” The practice, which involves the rapid purchasing, selling, and repurchasing of stocks, is not technically illegal, but Pimco in its prospectus says it does not tolerate such trading, also known as short term trading.

Mr. Howell testified that while at Pimco he reviewed each day’s trades and sent warning letters out to investors he determined were market timing, but was told by his superiors specifically not to allow Canary “to get caught up in our market timing net.”

Each month, Canary made on average between four and five “round trips,” the term used to imply the full cycle of buying and selling that is market timing. Calling such practices an “extreme” form of market timing, Mr. Howell said that under normal circumstances Pimco, which allows about that many round trips in an entire year, would have sent Canary a warning letter.

An SEC lawyer, Sam Puathasnanon, also said that Canary, after it was told by Pimco to cease trading by October 15, 2002, kept at it as late as November. Mr. Puathasnanon produced an e-mail that Mr. Howell received on November 8, 2002, from a superior that said: “Steve Treadway gave them until year-end.”

During cross-examination, defense attorney Stephen Ascher said Canary’s last multimillion-dollar trade came on November 7, 2002, which he said was “a lot closer to October than December 31.”

Mr. Howell, who was subpoenaed by the SEC, also testified that portfolio managers had more expertise in determining whether a client’s market timing was hurting other clients, and that he never talked to a portfolio manager about Canary’s market timing.

After the SEC again tried to prove Mr. Treadway’s knowledge of the practice, defense attorney Alan Levine argued that only members of Pimco Equity Advisors, including a former co-defendant, Kenneth Corba, knew about Canary’s violations, not Mr. Treadway, who was CEO of a separate branch, Pimco Advisors Distributors. Before the trial began, Mr. Corba, who knew about Canary’s market timing practice throughout 2002, reportedly settled and agreed to pay $200,000.