By my calculations there are 4 true Cinderella teams — that is, teams from schools that have not awarded an undergraduate degree to a single billionaire — remaining in the NCAA Tournament:  Butler, UNLV, Southern Illinois, and Pittsburgh.  Here is the billionaire breakdown of the Sweet 16:

USC (8) — Bradley Hughes, George Lucas, Edward Roski, Jr., Igor Olenicoff, Alan Casden, Scott Clark, Marc Benioff, Thomas Barrack

UCLA (7) — Steven Udvar-Hazy, , Alfred Mann, A. Jerrold Perenchio, Henry Nicholas III, Henry Samueli, John Anderson, Louis Gonda

Oregon (2) — Philip Knight, Timothy Boyle

Texas A&M (2) — George Mitchell, L. Lowry Mays

UNC (1) — Julian Robertson

Florida (1) — Jerry Zucker

Vanderbilt (1) — Thomas Frist, Jr.

Tennessee (1) — Charles Ergen

Kansas (1) — Philip Anschutz

Ohio State (1) — Leslie Wexner

Georgetown (1) — Michael Heisley, Sr.

Memphis (1) — Nancy Walton Laurie

Butler (0)

UNLV (0)

Southern Illinois (0)

Pittsburgh (0)

Previously.