Each bidder will have to electronically sign or fill out any registration documents. The costs to purchase service credit fall into two categories, depending on the type of eligible credit.Purchases can be made with post-tax dollars. 6.1 Buy and Hold: The Treasurer will generally use the passive investment strategy known as BUY. Download PDF BOE-502-A REV. I.2 Retained Assets. Please Download PDF BOE-63-A REV.