DMBS vs SPMB

DMBSCDoubleLine Mortgage ETF

SPMBAState Street SPDR Portfolio Mortgage Backed Bond ETF

In short

DMBS DoubleLine's mortgage desk in an ETF wrapper: an actively managed bond fund built to exceed the Bloomberg U.S. Mortgage-Backed Securities Index over a full market cycle, in a corner of the market almost everyone else simply indexes.

SPMB The no-frills way to own America's mortgage bonds. SPMB tracks the Bloomberg U.S. MBS Index for four basis points, a fraction of what the typical mortgage-bond ETF charges, and pays income monthly.

Stated mandate

DMBS The Fund seeks total return through capital appreciation and current income, exceeding the Bloomberg U.S. Mortgage-Backed Securities Index over a full market cycle.

SPMB The fund seeks to track, before fees and expenses, the price and yield performance of the Bloomberg U.S. MBS Index.

Why people hold it

• DMBS Active by design. Managers pick the mortgage bonds instead of copying the index, with a stated aim of exceeding the Bloomberg U.S. Mortgage-Backed Securities Index over a full market cycle.
• Pays monthly, matching the rhythm of the mortgage cash flows underneath it.
• Trades with decent everyday liquidity for an active bond ETF, and sits in the upper half of its mortgage-bond peer group on our review.
• A US agency mortgage mandate run inside a standard 1940 Act fund. No exotic wrapper, no K-1 surprises.

• SPMB Four basis points a year, against a 0.35% median for mortgage-bond ETFs. Cost is where this fund does its loudest talking.
• Runs the same Bloomberg U.S. MBS Index as iShares' MBB at the same 0.04% fee, and undercuts MBBA, which tracks that index for far more.
• Roughly 2,700 mortgage bonds in a single line item, inside a multi-billion-dollar fund that trades actively, with distributions paid monthly.
• Trading since 2009, and one of the strongest implementations in its mortgage-bond peer group.

Worth knowing

• DMBS At 0.39% a year it runs above the typical mortgage-bond ETF, and roughly ten times index trackers like VMBS (0.03%) and MBB (0.04%). Active management has to earn that gap.
• Launched in 2023, so its track record is short relative to the full market cycle the fund itself uses as the yardstick.
• Results ride on the manager's security selection rather than the benchmark, which means the gap versus the index can cut either way.

• SPMB Homeowners refinance when rates fall, so mortgage bonds get paid back early and rally less than Treasuries. That quirk is built into the index, not the fund.
• Prices move with interest rates and the monthly payout floats with the portfolio. This is a bond fund, not a cash substitute.
• US mortgages only. No Treasuries, no corporates, no credit spice. A building block for a bond sleeve rather than the whole sleeve.

Full DMBS profile⁠

Full SPMB profile⁠