States differ in whether they include sales through a "Marketplace Facilitator" (MF) -- such as Amazon, Walmart, eBay, etc. -- when measuring a company's economic nexus. Here is a breakdown:
States that include marketplace-facilitated sales
Alaska
California
Connecticut
DC
Hawaii
Idaho
Iowa
Kansas
Kentucky
Maryland
Michigan
Minnesota
Nebraska
Nevada
New Jersey
New York
North Carolina
Ohio
Rhode Island
South Carolina
South Dakota
Texas
Vermont
Washington
West Virginia
Wisconsin
States that exclude marketplace-facilitated sales
Alabama
Arizona
Arkansas
Colorado
Florida
Georgia
Illinois
Indiana
Louisiana
Maine
Massachusetts
Mississippi
Missouri
New Mexico
North Dakota
Oklahoma (if the MF collects sales tax)
Pennsylvania (if the MF collects sales tax)
Tennessee
Utah
Virginia
Wyoming