Central banks are digging deeper into their tool kits in search of innovative ways to unclog bank lending and keep a weakening world economy afloat.

With the fifth anniversary of the financial crisis approaching in August, policy makers from the Federal Reserve, the European Central Bank and the Bank of England all meet within 24 hours next week. Central banks, facing a global recovery that's sputtering even after they delivered trillions of dollars of liquidity and near-zero interest rates, are having to consider fresh strategies to combat the slowdown.

"Central banks are thinking hard about other ways to spur their economies and get credit into corners of the economies that need it and aren't getting it," said Nathan Sheets, global head of international economics at Citigroup Inc. in New York and director of the Fed's international finance division until last year.