 He formed with George D. Sheldon and others in 1899 the so-called Barney-Sheldon real estate syndicate.Besides serving as president and a director of the Knickerbocker Trust Company, Barney was president and a director of the New York Loan and Improvement Company; a trustee of the Bank for Savings; a director of the Brooklyn Life Insurance Company, Lawyers' Mortgage Insurance Company, United States Realty and Improvement Company, Title Insurance Company of New York, New York Mortgage and Security Company, Century Realty Company, Hudson Mortgage Company and Chelsea Realty Company; and a shareholder of the Santa Cecilia Sugar Company, Cuba Hardwood Company, Cuba Northeastern Railroad, American Ice Company, Ice Securities Company, Eastern Steamship Company, Metropolitan Steamship Company, Dominion Iron Company Ltd., Dominion Iron and Steel Company Ltd., and the Hudson Navigation Company (the Hudson River Night Line).He was also an investor in the New York City Subway and the Metropolitan Opera and Real Estate Company.