Charles Schwab Corp. has partnered with Pacific Investment Management Co. to offer wealthy clients in or approaching retirement a managed municipal bond laddering product.

Responding to client demands for greater stability and consistent income, Schwab launched four separately managed muni-ladder accounts.

A common fixed-income technique, laddering entails buying bonds across a spectrum of maturities. As the bonds in the bottom rung mature, the principal is reinvested in long-term bonds.

That ensures the portfolio is always evenly distributed across a range of maturities, offering some protection against swings in interest rates or shifts in the yield curve.

Schwab is offering two maturity ranges — one to 12 years, and one to 18 years.

For each maturity range, Schwab offers a national product and a California product.

Andy Gill, senior vice president of fixed income for the San Francisco-based company, said what distinguishes these ladders from the ladder a typical financial adviser would build is Pimco’s expertise.

“Pimco offered us the best solution for our clients in terms of overall value, credit quality, and monitoring,” he said.

Pimco will scour the market for superior credits to include in the rungs upon initial investment as well as in reinvesting maturing principal. It will select bonds rated A-minus or better.

Once invested, the Newport Beach, ­Calif.-based investment manager will continue to monitor the credits and ferret out any it deems unfit for investment-grade portfolios.

Pimco also enjoys “institutional purchasing power” in buying the bonds for Schwab’s clients.

Schwab, which oversees $1.42 trillion in client assets, conducted a study recently that found investors age 55 to 70 are “more concerned with income generation and principal preservation than portfolio growth when compared to younger investors.”

That, Gill said, is the rationale behind offering more laddering capabilities to investors.

Municipal ladders are a safe, effective way to deliver dependable income, he said.

The strategy requires a $250,000 minimum investment, which Gill said is the amount Pimco needs to create a sufficiently diversified ladder.

He said the product is targeted at investors with at least $1 million in investable assets.

The product will charge 0.35% of the invested assets annually for accounts of $1 million or less. The fee will drop to 0.3% for accounts between $1 million and $5 million, and 0.25% for investments above $5 million.

Gill said these fees compare favorably with the roughly 0.65% Schwab charges on most other separately managed accounts.

He said Pimco has conducted research showing it can generate the most value using ladders with maturities from one to 12 years and one to 18 years.