Washington State Investment Board, Olympia, may put up for bid $18 billion in indexed equity assets, now managed by Barclays Global Investors, as part of a normal review, said Gary Bruebaker, chief investment officer for the $53 billion system. That total includes $16.5 billion invested in a broad-market portfolio for the defined benefit plan, plus three portfolios for the states defined contribution system. The board is expected to vote on the proposal Thursday and issue an RFP in early May. The deadline for proposals will be June 14. R.V. Kuhns is consultant.