Section 10. Any documentary materials or data made or received by any member or employee of the corporation, to the extent that such material or data consist of trade secrets, commercial or financial information regarding the operation of any business conducted by an applicant for, or recipient of, any form of assistance which the corporation is empowered to render, or regarding the competitive position of such applicant in a particular field of endeavor, shall not be deemed public records and shall not be subject to the provisions of section ten of chapter sixty-six; provided, however, that if the corporation purchases a qualified security from such applicant, the commercial and financial information, excluding trade secrets, shall be deemed to become a public record of the corporation and subject to the provisions of said section ten of said chapter sixty-six after the sale of the corporation's qualified security. Any discussion or consideration of such trade secrets or commercial or financial information, may be held by the board, or any subcommittee of the board, in executive sessions closed to the public, notwithstanding the provisions of section eleven A and one-half of chapter thirty A; provided, however, that the purpose of any such executive session shall be set forth in the official minutes of the corporation and business which is not related to such purpose shall not be transacted, nor shall any vote be taken during such executive sessions.