Offered here is what some collectors call a "ghost flag" - something that is all but missing from the collecting hobby. This is a 1999 US Open flag that is autographed by the Payne Stewart, who passed away just 4 months after this historic tournament.

Flag collecting was in its infancy in 1999 - very few PGA Tour events even sold souvenir flags. But the US Open did, and this "course" version was actually sold at Pinehurst during the 1999 US Open (there was a different "USGA version" that could be purchased through the USGA catalog). Thankfully an autograph collector used this 1999 US Open flag obtained from Pinehurst to get the autographs of 16 different US Open Champions. Most importantly, he obtained the autograph of that week's winner Payne Stewart (signed on the left side of the logo - a little hard to see in a photo). Here is a complete list of the US Open Champions that have autographed this impressive flag:

Payne Stewart - 1991, 1999 US Opens (deceased)
Arnold Palmer - 1960 US Open (deceased)
Orville Moody - 1969 US Open (deceased)
Ken Venturi - 1964 US Open (deceased)
Gene Littler - 1961 US Open (deceased)
Tommy Bolt - 1958 US Open (deceased)
Tony Jacklin - 1970 US Open
Hale Irwin - 1974, 1979 US Opens
Lou Graham - 1975 US Open
Jerry Pate - 1976 US Open
Andy North - 1978 US Open 
Fuzzy Zoeller - 1984 US Open
Scott Simpson - 1987 US Open
Lee Janzen - 1993 US Open
Steve Jones - 1996 US Open
Ernie Els - 1994, 1997 US Opens

Letter of Authenticity from James Spence Authentication (JSA)