Not so, even though it was erroneously wideky reported as a pardon, it was a just a commutation of his sentence.
From the official government document:
William Walters – President Trump commuted the sentence of William Walters. This commutation is supported by former Majority Leader Harry Reid, former Governor Jim Gibbons, former Representative Shelley Berkley, former Clark County Sheriff William Young, former Police Commissioner Bernie Kerik, numerous professional golfers including Butch Harmon, David Feherty, Peter Jacobsen, and Phil Mickelson, and former 60 minutes correspondent Lara Logan. Mr. Walters was sentenced to 5 years imprisonment for insider trading. Since his conviction, Mr. Walters has served nearly 4 years of his prison sentence and has paid $44 million in fines, forfeitures, and restitution. In addition to his established reputation in the sports and gaming industry, Mr. Walters is well known for his philanthropic efforts and was previously named Las Vegas’ Philanthropist of the Year.