Getting Paid to Extend: The Case for Muni Duration

Treasury’s decision to at least double 10- to 30-year buybacks is a policy signal, not a technical footnote. It argues for adding duration and positioning for a flatter curve. History is on the side of the muni bid into year-end. Across 22 election cycles since 1982, the outcomes in which Republicans lose at least one chamber have been among the friendliest for 10-year AAA MMD. Credit is past peak but not impaired. The combined Moody’s/S&P upgrade-to-downgrade ratio fell to 0.7-to-1 in 2Q26, and multi-notch downgrades hit their highest level since 3Q18. Municipals are not cheap. Investment grade spreads sit in the 8th percentile of their 52-week range, so this is a rate and curve trade, not a spread trade.

Municipals spent the summer going nowhere in particular. That looks to be ending. On Wednesday August 19, the U.S. Treasury announced it will at least double its purchases of 10- to 30-year bonds — a deliberate attempt to pull down the long end while the department continues to fund itself at the front. The closest analog is the Federal Reserve’s 2011 “Operation Twist,” with one important difference: this time the twist is being engineered by the issuer rather than the central bank. The market reaction was immediate and lopsided. Over the week ended August 19, 10- and 30-year Treasury yields fell 3bp and 5bp, respectively, while 10- and 30-year AAA MMD cheapened 7bp. That divergence cost tax-exempt investors: the ICE BofA Municipal Master Index returned -0.39% for the week, roughly 80bp behind Treasuries, corporates and taxable munis, and August month-to-date performance of 0.41% now trails those sectors by more than 30bp. Tax-exempt investment grade is still ahead year-to-date, but the cushion is thinner than it was two weeks ago. We read the lag as an opportunity rather than a warning. Near-record short positioning in ultra-long bond futures had built through the bear-steepening episode that began in mid-June, and Treasury’s announcement is the kind of catalyst that forces that positioning to unwind. Municipals typically follow, with a delay.

What that means for portfolios: consider adding duration while yields are still high and position for a potentially flatter curve. The AAA curve remains steep by any recent standard, with 1s30s at 210bp and 1s10s at 88bp, both at or near their three-month wides. Investors are being paid unusually well to extend. Valuation is the one place to be careful. Muni/Treasury ratios sit at 61.2% in 3 years, 71.2% in 10 and 87.0% in 30 — neutral against three-year history, with the 10-year point modestly cheap on a three-month basis. Investment grade spreads of 13bp sit in the 8th percentile of their 52-week range and high yield spreads of 153bp in the 15th. Municipals are not cheap. The case for owning them here is rate direction and curve shape, not spread compression.

Roughly 470 Congressional seats are on the ballot November 3. Midterms are historically unkind to the party in power, and current polling reflects that: the RealClearPolitics generic ballot favors Democrats by 6.4 points, and seven in ten fund managers in BofA’s August Global Fund Manager Survey expect Democrats to take the House. A split outcome — Democratic House, Republican Senate — is the single most-expected result, at 47%. That matters for tax-exempt rates. Looking at 10-year AAA MMD across the last 22 election cycles, the “unified Republican control going in, at least one chamber lost coming out” scenario has been among the most bullish in the sample: yields drift modestly higher into e...