Koosharem Corp., which does business as the Select Family of Companies, expressed interest in purchasing Walnut Creek CA-based Westaff Inc. (NASD: WSTF), according to a filing with the U.S. Securities and Exchange Commission.

Koosharem made three previous offers to buy Westaff, according to the filing, but Westaff did not engage in "meaningful discussions." The parties, however, struck a confidentiality agreement on Oct. 9 to allow for the transfer of information.

The filing said Koosharem is looking at acquiring 100% of Westaff's stock, but a subsequent filing by Westaff said previous proposals from Koosharem did not include the 49.3% of shares owned by DelStaff LLC.

Koosharem's owners already own 9.4% of Westaff's stock.

The Select Family of Companies ranks as the 11th-largest staffing firm in the U.S. based on 2007 revenue. Westaff ranks as the 34th-largest by U.S. revenue.