The Bank of Japan decided Wednesday to start a multiyear program by late July to buy asset-backed securities worth up to 1 trillion yen to make it easier for small and medium-size companies to raise funds.

The BOJ said its Policy Board agreed in a unanimous vote during a two-day meeting that the operation will involve purchases of risky securities and will end in March 2006.

It will be the first time the central bank has purchased such private, risk-bearing securities. Until now, the BOJ has mainly bought government bonds to pump liquidity into the financial markets and prevent its finances from deteriorating.