Three of the six were members of the Rifkin family, which sold OmniSource to Steel Dynamics for $1.1 billion, according to The Journal Gazette of Fort Wayne.
Fast-growing Steel Dynamics and OmniSource both are in Fort Wayne. About 2,700 of Steel Dynamics' 6,700 employees are with OmniSource.
One brother, Danny Rifkin, who was OmniSource chief operating officer and Steel Dynamics executive vice president, told the newspaper the separation was prompted by philosophical differences over strategic direction that developed after the close of the Oct. 26 transaction.
Rifkin described the discussions with Steel Dynamics executives as respectful and professional.
Steel Dynamics shares have climbed steadily since 2003, rising to nearly $40 from about $3.