NEW YORK -- A prosecutor and a defence attorney have both told jurors at a New York insider trading trial that a stock trade by golfer Phil Mickelson aids their case.

The golfer's name arose as Assistant U.S. Attorney Michael Ferrara and defence attorney Barry Berke previewed arguments Wednesday at the trial of professional gambler William "Billy" Walters.

Ferrara says Walters wanted friends to share the benefits of his secrets. Berke says no one with secrets would want to attract scrutiny by tipping off a famous golfer.

Prosecutors say Walters earned more than $40 million illegally by trading on tips from a former board member at Dean Foods Co., one of the nation's largest processors of milk for retailers. They say the tips occurred from 2008 to 2013.

Berke says Walters is not guilty.