The cost bond filed by a claimant pursuant to Sec. 403.26(a)(4) shall be a corporate surety bond. However, upon a showing to the satisfaction of the Commissioner or his delegate that such claimant is unable to furnish a corporate surety bond, such claimant may file a cost bond with individual sureties acceptable to the Commissioner or his delegate or, in lieu of such cost bond with corporate or individual sureties, he may deposit collateral pursuant to Sec. 403.29.