CalSTRS Oct. 13 will consider adding a national credit enhancement program to its existing regional activities. Started five years ago, the internally managed regional program guarantees bonds issued by other entities, using the Sacramento-based California State Teachers Retirement Systems AAA rating. The institutions then split the cost savings between them. The $100 billion funds total exposure as of the end of August was $700 million. Board members will look at a national program being offered by Consortium Financial Group, a new unit of Canadian Imperial Banking Corp. CFG hopes to have $2.6 billion in credit guarantees in place by the end of the first year and $4.8 billion by the end of the second year. If the CalSTRS board approves the concept, fund officials will examine externally run programs, said Patrick Mitchell, chief investment officer.