New York Mercantile Exchange hopes to convert from a member-owned, not-for-profit organization to a for-profit company on Wednesday, exchange officials said. The Chicago Mercantile Exchange will make the same conversion Monday. Demutualization plans for both exchanges have followed a similar timeline for a year. NYMEX got IRS approval for a tax-free conversion of its memberships to stock shares on Oct. 24. The CME got its IRS approval Nov. 8.