瑞穗銀行
was founded on March 12, 1991 for the express purpose of constructing and operating the railway line. It is a third-sector company, and, as of 1 April 2013, 91.32% of shares are held by the Tokyo Metropolitan Government, 2.41% by JR East, 1.77% by Shinagawa Ward, 0.70% by Mizuho Bank, 0.46% by MUFG Bank, 0.34% by Sumitomo Mitsui Banking Corporation, and the remaining 3% by 41 other companies.