U.S. Interest Rate on Reserve Balances

USIORB is the published interest rate on reserve balances, carried over and recorded as-is without transformation, filtering, or interpolation. It is the administered rate that the monetary authority decides to pay on reserve balances held at the central bank and publishes in percent per annum, so the value is the announced level itself rather than a KRED estimate.

The rate is not a market-clearing price but a controlled level chosen within an operating-target regime, and its mechanics are set out in the theory of operating targets and standing-facility corridors (Bindseil 2004; Borio 1997). Where reserves are ample the rate works as the floor below which the overnight rate does not settle, pinning the day-to-day overnight rate within a corridor (Bartolini, Bertola, and Prati 2002).

The overnight market this rate addresses divides into unsecured interbank lending and secured repurchase transactions, the former determined by daily clearing and measured at the level of individual transactions, the latter defined as a financing rate that responds to collateral scarcity (Hamilton 1996; Furfine 1999; Duffie 1996). Subtracting the secured overnight rate from this administered rate yields one leg of the reserve-conditions spread that KRED publishes, and what is served here is that leg as a raw series.

Through the term-structure lens the rate is the current administered short rate whose expected path plus a premium determines longer yields (Hicks 1939). The yields so determined are computed within the yield-to-maturity convention and the zero-coupon measurement tradition (Macaulay 1938; McCulloch 1971; Nelson and Siegel 1987; Gürkaynak, Sack, and Wright 2007).

The series is recorded as a daily step function, changing only on decision dates and otherwise flat.

KRED applies no transformation to USIORB and performs neither rescaling, deflating, smoothing, nor annualizing. The methodology is therefore confined to the measurement basis by which an administered remuneration rate comes to exist.

The rate is not an average formed in transactions but a level chosen by a policy committee and published as a percentage per annum, which constitutes an operating-target construction (Borio 1997; Bindseil 2004). That level is maintained within a corridor through open-market operations and standing facilities, and where reserves are ample it functions as the floor for the overnight rate (Bartolini, Bertola, and Prati 2002).

The daily microstructure of the overnight rates this remuneration rate governs is measured at the level of individual transactions (Hamilton 1996; Furfine 1999), and the unsecured rate is distinct from the secured repurchase rate that responds to collateral scarcity, a distinction preserved intact in the raw series (Duffie 1996).

To situate this short rate within the measured yield curve, the same level serves as a reference point for zero-coupon and forward-rate construction. That construction begins from the yield-to-maturity concept and continues through spline recovery, parametric fitting and its extension, operational daily curve building, and comparative evaluation, closing with the duration mapping (Macaulay 1938; McCulloch 1971, 1975; Vasicek and Fong 1982; Nelson and Siegel 1987; Svensson 1994; Gürkaynak, Sack, and Wright 2007; Bliss 1997; Fisher and Weil 1971). None of these adjustments are applied to USIORB itself, which remains at the recorded level.

The interest rate on reserve balances is the implementation instrument by which the monetary authority sets the overnight opportunity cost of holding reserves directly, and the operating-target framework that assigns it this role is formalized within the standard apparatus of monetary policy implementation (Bindseil 2004; Borio 1997). Steering the rate within a corridor is the act of controlling what reserve holding earns (Bartolini, Bertola, and Prati 2002), while reserve supply and this remuneration rate jointly determine the daily overnight rate, an effect traced at the transaction level (Hamilton 1996; Furfine 1999).

Where reserves are ample the secured overnight rate stays near this administered level, but as collateral becomes scarce the secured rate is pushed above that floor (Duffie 1996). Reading this rate alongside the secured overnight rate is therefore the standard way to judge whether reserves are ample or scarce, and the KRED reserve-conditions spread summarizes that reading in a single number.

Because the current remuneration rate and its expected path move the entire term structure (Hicks 1939), its economic reach extends beyond the overnight market to the whole of the measured yield curve (Macaulay 1938; McCulloch 1971; Nelson and Siegel 1987; Svensson 1994; Gürkaynak, Sack, and Wright 2007).

Because the remuneration rate is the certain return on holding reserves, it is the baseline for bank funding desks deploying overnight cash, and the gap between it and the secured financing rate governs the choice between holding reserves and lending against collateral (Duffie 1996). Its daily formation and its steering within a corridor are well documented (Hamilton 1996; Furfine 1999; Bartolini, Bertola, and Prati 2002; Bindseil 2004).

In valuation the level anchors the short end of the discount curve, so it enters bond pricing and interest-rate risk management directly. The channel runs through the duration concept that maps yield to the timing of cash flows and the term-structure duration that underlies immunization (Macaulay 1938; Fisher and Weil 1971).

The zero-coupon and forward curves used to discount and hedge are built from this short rate, and their construction runs from splines through parametric forms to daily curve building and has been compared method against method (McCulloch 1971, 1975; Vasicek and Fong 1982; Nelson and Siegel 1987; Svensson 1994; Gürkaynak, Sack, and Wright 2007; Bliss 1997). Treasury and asset-liability desks therefore treat this rate as the base from which carry, rollover cost, and discount factors are computed.

On the 1,779 daily observations spanning 2021-07-29 to 2026-06-11, fit with a constant and trend, the unit-root battery agrees that the interest rate on reserve balances is integrated of order one. The augmented Dickey-Fuller test of Dickey and Fuller (1979), in the ARMA-consistent lag-augmented form of Said and Dickey (1984) and with lag length set as in Ng and Perron (2001), does not reject a unit root with p = 0.9847, the nonparametric Phillips and Perron (1988) test concurs with p = 0.9876, and the Kwiatkowski et al. (1992) stationarity test rejects its trend-stationary null at p < 0.01, so the verdict is an unambiguous I(1). The GLS-detrended power escalation of Elliott, Rothenberg, and Stock (1996) is reserved for ambiguous outcomes under the house protocol and is not required on this clean reading.

Because the level is integrated, the mean-shift and serial-correlation diagnostics are run on the first difference, the stationary object those procedures require, since a break search or a portmanteau on an integrated level would spuriously segment and read near-unit autocorrelations (Bai and Perron 1998; Perron 1989). The multiple-break procedure of Bai and Perron (1998), computed by the dynamic-programming algorithm of Bai and Perron (2003), finds a single break in the mean of the differenced rate, at 2023-05-05, read as parameter instability in the sense of Andrews (1993). The remuneration rate is held constant between monetary-policy decisions, so its first difference is a sparse jump sequence close to white noise, and the Ljung and Box (1978) portmanteau, refining the original Box and Pierce (1970) form, fails to reject the white-noise null on that difference with Q = 0.07 at lag 10 and Q = 0.13 at lag 20, p = 1.000 and p = 1.000, while the automatic portmanteau test of Escanciano and Lobato (2009) concurs with a statistic of 1.70 at p = 0.193.

The series is daily and has no low-integer seasonal period, so the seasonal-unit-root machinery of Hylleberg et al. (1990) and the Canova and Hansen (1995) seasonal-stationarity test are inapplicable and are deliberately not run, the degeneracy of the seasonal auxiliary regression at a daily period being the standard ground (Beaulieu and Miron 1992; Ghysels and Osborn 2001).