SPAB vs TPLS

SPABAState Street SPDR Portfolio Aggregate Bond ETF

TPLSCThornburg Core Plus Bond ETF

In short

SPAB A 2007-vintage core bond fund priced at 0.03%: roughly 8,500 US investment-grade bonds in one ticket, at the same rock-bottom fee the household names charge for the same index.

TPLS Thornburg's 2025 debut in the crowded aggregate-bond aisle, and it refuses to stay in the aisle: an active core-plus mandate that can wander into emerging market bonds, bank loans and structured debt, paying monthly.

Stated mandate

SPAB The fund seeks to track the price and yield performance of the Bloomberg U.S. Aggregate Bond Index before fees and expenses, providing broad exposure to U.S.-dollar-denominated investment-grade bonds.

TPLS The fund invests in a diversified portfolio of fixed-income instruments, including emerging market bonds, bank loans, and loan participants.

Why people hold it

• SPAB 0.03% a year against a 0.36% median for its peer group, and the same ticket price as AGG, SCHZ and BBAG on the identical index.
• Roughly 8,500 dollar-denominated investment-grade bonds in one line item, tracking the Bloomberg U.S. Aggregate Bond Index. Diversification you could not assemble bond by bond.ssga.com
• Trades actively and has tracked its index closely, putting it among the stronger implementations in the core-bond group.
• Running since 2007, now a multi-billion-dollar fund, and it pays monthly rather than quarterly.

• TPLS Core plus, and the plus is real: the mandate reaches past Treasuries and corporates into emerging market bonds, bank loans and loan participations.
• Pays income at least monthly, so coupons arrive on a steady rhythm rather than a quarterly lump.
• What it holds lines up closely with the wide-ranging mandate it advertises. No index-hugger wearing an active label.
• Plain 1940 Act fund structure: ordinary ETF plumbing, 1099 at tax time, no partnership paperwork.

Worth knowing

• SPAB Bond prices move opposite yields. When rates rise the index falls and the fund follows it down; a 0.03% fee cannot cushion that.
• AGG, SCHZ and BBAG hold the same declared index at the same 0.03%. Picking among them comes down to spreads and platform, not the portfolio.
• Investment grade and US dollar only by mandate: high yield and foreign-currency debt sit outside the remit.ssga.com

• TPLS The 0.45% fee is active-manager pricing in a category where index anchors like BND and SPAB charge 0.03%. The roaming mandate has to earn that gap.
• Small and thinly traded, which tends to mean wider bid-ask spreads than the giants of the aggregate-bond group.
• Launched in 2025, so the record is short. Thornburg also discloses that distributions can include return of capital, meaning part of a payout may be your own money back.

Full SPAB profile⁠

Full TPLS profile⁠