Hedge fund HBK Investments, which last summer signed on for LEED Platinum hopeful Bank of America Tower's 40th floor at $135 per square foot, has officially terminated its commitment for 12,000 square feet of that space. The Dallas-based firm will still retain 24,000 square feet on the 40th floor and the Dursts will now seek to lease the freshly freed space for an incredible $185 per square foot. The only space in the building that remains in addition to HBK's former space is 30,000 square feet on the 37th floor, where the Dursts are asking the same rent; the family will consider partitioning either space into blocks for smaller tenants. According to Eric Engelhardt, one of Durst's vice presidents for leasing, "[t]here is a greater universe of smaller tenants looking for high end space." (To that end, note 510 Madison Avenue, where each full-floor block of space is less than 15,000 square feet and the Macklowes have only signed up one tenant to date after coming close to inking Apple a few weeks ago).