Pimco, the world’s largest bond-fund manager, filed with the Securities and Exchange Commission to roll out six new bond ETFs—five passive and one actively managed—joining an already crowded field of fixed-income exchange-traded funds.

Most of the proposed funds are focused on corporate debt with varying credit qualities and maturities, but the Newport Beach, Calif.-based firm also filed with the SEC to roll out a dollar-denominated emerging markets sovereign debt ETF and an actively managed ETF based on Build America Bonds, or BABs.

The new offerings come at a time when bond investors are growing concerned about selling that’s sure to follow interest rate increases by the Federal Reserve aimed at keeping inflation at bay. Bond prices fall when interest rates rise, and investors are looking for safe havens before credit starts tightening. The Fed cut official lending rates to almost zero amid the worst economic downturn since the 1930s.

The passive ETFs include the Pimco 0-3 Year Banking Sector Corporate Bond Index Fund; the Pimco 1-5 Year High Yield Corporate Bond Index Fund; the Pimco Emerging Markets Aggregate U.S. $ Denominated Bond Index Fund; the Pimco High Yield Corporate Bond Index Fund; and the Pimco Investment Grade Corporate Bond Index Fund. The actively managed ETF is the Pimco Build America Bond Strategy Fund.

The fund company didn’t disclose management fees or ticker symbols in the March 10 filing, but did say the funds would trade on the NYSE Arca.

The Bond ETFs will track a family of Merrill Lynch benchmarks through a sampling strategy, meaning the fund managers won’t own all the securities in any given index.

The 0-3 Year Banking Sector Corporate Bond fund will own investment-grade debt issued by banks with anywhere from one month to less than three years to maturity. Each issue must have a minimum outstanding face value of $250 million and a fixed coupon schedule. The fund will also be able to use derivatives.

The 1-5 Year High Yield Corporate Bond fund and the High Yield Corporate Bond Fund will both consist of dollar-denominated, U.S.-issued, junk-quality debt. The portfolios are capitalization-weighted based on the bond’s amount outstanding, but each security has its weight in the mix capped at 2 percent. Each issue must have at least $100 million of outstanding face value and a fixed coupon.

Pimco’s Investment Grade Corporate Bond Index Fund will consist of investment-grade issues in the U.S. market with at least a year remaining until maturity.

Pimco’s dollar-denominated, emerging markets fund will hold sovereign and corporate debt that is both high yield and investment grade and has at least a year remaining to maturity. The portfolio will be rebalanced monthly and may use derivatives as well.

Build America Bond ETF

Pimco isn’t the first fund company to issue an ETF of BABs, but Pimco’s is the first actively managed offering.

The Pioneer in the space is PowerShares, which launched the PowerShares Build America Bond Fund (NYSEArca: BAB) in November 2009. It has attracted nearly $200 million in assets. The BABs program, launched in April of last year, is part of the Obama administration’s efforts at reviving the economy.