Appeal from the United States District Court for the District of Oregon Janice M. Stewart, Magistrate Judge, Presiding. D.C. No. 3:07-CV-01244-ST.
The opinion of the court was delivered by: Ikuta, Circuit Judge
Argued and Submitted May 5, 2009-Portland, Oregon
Before: William A. Fletcher, Carlos T. Bea and Sandra S. Ikuta, Circuit Judges.
Opinion by Judge Ikuta; Concurrence by Judge W. Fletcher
Charles Lee Reynolds appeals from the denial of his petition for a writ of habeas corpus under 28 U.S.C. § 2241, contending that the Federal Bureau of Prisons ("BOP") erred by refusing to issue an order under 18 U.S.C. § 3621(b) that retroactively (nunc pro tunc) designated the Montana state prison where Reynolds served his state sentence as the place where he began serving his federal sentence. Such an order, in effect, would have deemed that Reynolds's federal sentence ran concurrently with his state sentence, and thus would have shortened Reynolds's term of federal imprisonment by the amount of time he served in state prison. We affirm the district court's denial of the petition.
On October 3, 2002, Reynolds attempted unsuccessfully to cash a forged cashier's check at a bank in Ennis, Montana. Notified by the bank, state police arrived, and Reynolds fled in his car. Following a high-speed chase, the police captured Reynolds and booked him in the Madison County, Montana, jail in the early hours of October 4. His booking sheet indicated that his arrest was "pursuant to a warrant." Five hours after booking, Reynolds's arresting officer received a copy of a federal warrant issued for Reynolds, which listed offenses relating to identity theft and interstate flight to avoid prosecution. On October 29, the county attorney for Madison County charged Reynolds by Information with forgery, identity theft, and violation of the terms of three suspended sentences. The county attorney for Lewis and Clark County, Montana, filed additional charges against Reynolds shortly thereafter.
Before Reynolds was tried or convicted in state court, the federal district court in Montana issued a writ of habeas corpus ad prosequendum, which released Reynolds to federal custody to answer federal criminal charges. On May 22, 2003, Reynolds pleaded guilty to identity theft, 18 U.S.C. § 1028(a)(7), and bank fraud, 18 U.S.C. § 1344. The district court judge, Judge Charles Lovell, sentenced Reynolds to 71 months' imprisonment for each count, with the sentences to be served concurrently. That same day, Reynolds was returned to state custody.
Reynolds pleaded guilty to charges in Lewis and Clark County on July 24, 2003. The state court sentenced Reynolds to a term of fifteen years in state prison, with five years suspended. The state judge ordered Reynolds's sentence for certain charges to run concurrently "with the federal sentence imposed on defendant." Four months later, the state court in Madison County sentenced Reynolds to an additional five years in state prison, and likewise specified that this sentence should "be served concurrently with Defendant's sentences in Lewis and Clark County, Montana, and U.S. District Court to the extent which they overlap." Reynolds served 51 months in state prison.
While in state prison, Reynolds petitioned the BOP to designate nunc pro tunc the Montana state prison as the "place in which he may serve his federal sentence" pursuant to 18 U.S.C. § 3621(b).*fn1 Reynolds sought a declaration that his federal sentence began when he was first incarcerated in state prison. In support of his request, Reynolds noted that the Montana courts had ordered that Reynolds's state sentence was to run concurrently with his federal sentence. The BOP determined, however, that the federal court had not ordered that his sentences run concurrently, and confirmed this interpretation with Judge Lovell. The BOP denied Reynolds's request in December 2004.
On December 22, 2006, Reynolds was released from state prison and transferred to federal custody. He thereafter renewed his request for retroactive designation of the state prison as the place where he began serving his federal sentence. In response, the BOP again asked Judge Lovell to indicate "the Court's position on a retroactive designation" in Reynolds's case. In its letter, the BOP explained that if Reynolds's request were granted, he would have a projected release date of July 17, 2008; otherwise, his projected release date would be February 17, 2012. In a letter dated October 2007, Judge Lovell stated that he had "no comment on [the BOP's] consideration of Defendant Reynolds for retroactive designation of the state institution for the service of the federal sentence."
The BOP denied Reynolds's request in November 2007 based on the factors listed in 18 U.S.C. § 3621(b), specifically the nature and circumstances of Reynolds's offense, Reynolds's history and characteristics, and Judge Lovell's response. Reynolds appealed this administrative determination. The BOP denied the appeal, stating that "[t]he federal judgment was silent regarding the execution of your service. As such, multiple terms of imprisonment imposed at different times are deemed consecutive unless the court dictates otherwise." Furthermore, the BOP explained, Reynolds did not merit nunc pro tunc designation of the state prison under the factors enumerated in 18 U.S.C. § 3621(b). Reynolds's actions (as noted by the federal sentencing court) posed a "significant danger to the community," Reynolds's flight from state authorities created a "substantial risk of death or serious bodily injury to others," and he had attempted to influence a witness. Furthermore, the BOP noted that in light of "the career nature of [his] criminal activities, lengthy criminal history to include violence, and the characteristics of the instant offense, the likelihood of [his] recidivism is highly probable."
Reynolds filed a petition for writ of habeas corpus under 28 U.S.C. § 2241. The district court denied the petition, and Reynolds timely appealed. In November 2009, while this appeal was pending, Reynolds renewed his request for a nunc pro tunc designation of the Montana state prison where he had been incarcerated as the place where he began service of his federal sentence. The BOP contacted Judge Lovell for a third time; this time, the judge responded that "since the objectives of sentencing have apparently been largely met in his case, I have no objections to your suggestion for a retroactive designation." On November 18, 2009, the BOP granted Reynolds's request. Based on this ruling, the BOP determined that Reynolds was entitled to immediate release. His five-year term of supervised release thus began on November 20, 2009.
Before addressing the merits of Reynolds's petition, we must address the government's argument that Reynolds's challenge to the BOP's November 2007 decision is moot because it was superseded by the BOP's November 2009 decision.
 We conclude that Reynolds's petition is not moot. A challenge to a term of imprisonment is not mooted by a petitioner's release where the petitioner remains on supervised release and "[t]here is a possibility that [petitioner] could receive a reduction in his term of supervised release under 18 U.S.C. § 3593(e)(2)." Mujahid v. Daniels, 413 F.3d 991, 995 (9th Cir. 2005); accord Arrington v. Daniels, 516 F.3d 1106, 1112 n.4 (9th Cir. 2008); United States v. Verdin, 243 F.3d 1174, 1179 (9th Cir. 2001). Reynolds is currently scheduled to remain on supervised release until 2014. In support of his petition challenging the BOP's November 2007 decision, Reynolds claims he is entitled to a recalculation of his release date to July 17, 2008, and asserts that he was overincarcerated for sixteen months: from July 17, 2008 to his actual release date of November 20, 2009. A court could consider this alleged period of over-incarceration under 18 U.S.C. § 3583(e) as a factor weighing in favor of reducing the term of supervised release. See United States v. Johnson, 529 U.S. 53, 60 (2000). Furthermore, because the BOP's November 2009 decision did not recalculate Reynolds's release date to July 17, 2008, it did not give Reynolds the relief he requested in his petition for habeas corpus. Accordingly, we reject the government's contention that Reynolds's appeal is moot.
We turn to the merits of Reynolds's claim that the BOP erred in November 2007 when it denied his request for nunc pro tunc designation of the Montana prison as the facility for service of his federal sentences. We review de novo the denial of a petition filed under 28 U.S.C. § 2241, Bowen v. Hood, 202 F.3d 1211, 1218 (9th Cir. 2000), reviewing underlying factual findings for clear error, McNeedly v. Blanas, 336 F.3d 822, 826 (9th Cir. 2003).
 We begin with a brief overview of the law applicable to federal courts and the BOP's determination of whether sentences should be served consecutively or concurrently. Under 18 U.S.C. § 3584, "[m]ultiple terms of imprisonment imposed at different times run consecutively unless the court orders that the terms are to run concurrently."*fn2 A court has the discretion, however, to order that multiple terms of imprisonment run concurrently when the court is imposing multiple terms on a defendant at the same time or is sentencing a defendant already subject to an undischarged term of imprisonment. Id. The discretion granted by this provision is limited in two respects. First, "concurrent sentences imposed by state judges are nothing more than recommendations to federal officials." Taylor v. Sawyer, 284 F.3d 1143, 1150 (9th Cir. 2002). Accordingly, "the court" referenced in § 3584(a) refers only to federal courts. Second, we have held that even federal courts "cannot order a sentence to run either concurrently or consecutively to a non-existent term." Id.; see 18 U.S.C. § 3584(a). In other words, a federal court cannot order a sentence to be served concurrently with a sentence, including a state sentence, that has not yet been imposed. Id.
During the sentencing process, federal courts must also consider the United States Sentencing Guidelines. See United States v. Carty, 520 F.3d 984, 991 (9th Cir. 2008) (en banc). Section 5G1.3 of the Guidelines provides that under certain circumstances, if a defendant is already subject to an undis-charged term of imprisonment for "relevant conduct," the sentencing court should adjust a defendant's sentence for the crime of conviction to take into account the time already served and should order the sentence to run concurrently with the remaining undischarged term of imprisonment.*fn3 This Guideline also includes the Sentencing Commission's policy statement that where there is an undischarged term of imprisonment, the district court should exercise its discretion "to achieve a reasonable punishment" for the offense. § 5G1.3(c).
Once the district court has discharged its sentencing function, the defendant is committed to the custody of the BOP, which has the authority to calculate the defendant's sentences in accordance with the district court's orders, as well as to designate the facility for service of such sentences. By statute, a federal sentence "commences on the date the defendant is received in custody" at the "official detention facility at which the sentence is to be served." 18 U.S.C. § 3585(a). The BOP has the authority to "designate the place of the prisoner's imprisonment." 18 U.S.C. § 3621(b). In exercising this designation authority, the BOP is directed to consider a range of factors, including "the nature and circumstances of the offense," "the history and characteristics of the prisoner," "any statement by the court that imposed the sentence" including any recommendation as to the type of correction facility, and "any pertinent policy statement" of the Sentencing Commission. Id.
 On its face, § 3621(b) gives the BOP only the administrative responsibility to identify the facility in which a federal prisoner will serve out the sentence imposed by the district court. The BOP has interpreted this statute, however, as authorizing it to issue a nunc pro tunc order designating a state prison as the facility for service of a federal sentence "when it is consistent with the intent of the federal sentencing court or with the goals of the criminal justice system." BOP Program Statement 5160.05 (January 16, 2003). Program Statement 5160.05 explains, "[w]hen a federal judge orders or recommends a federal sentence run concurrently with a state sentence already imposed the Bureau implements such order or recommendation, ordinarily by designating the state facility as the place to serve the federal sentence." The BOP will also consider "an inmate's request for pre-sentence credit toward a federal sentence for time spent in service of a state sentence as a request for a nunc pro tunc designation." The Program Statement requires the BOP to consider the inmate's request, and sets forth the procedure the BOP must follow in determining whether to designate a state prison for (in effect) concurrent service of a federal sentence. Such procedures require the BOP to ask the federal sentencing court if it has any objections to such designation.
We approved the BOP's approach under this Program Statement in Taylor v. Sawyer, 284 F.3d at 1148-49.*fn4 In that case, we considered and rejected the argument that the Program Statement's grant of authority to the BOP to issue a nunc pro tunc designation was inconsistent with § 3584 and thus invalid. Id. Instead, joining other circuits that had considered the issue, we concluded that "such a designation by the BOP is plainly and unmistakably within the BOP's discretion." Id. at 1149; see McCarthy v. Doe, 146 F.3d 118, 123 (2d Cir.1998) (holding that the BOP has the discretion to grant or deny a request for nunc pro tunc relief); Barden v. Keohane, 921 F.2d 476, 478 (3d Cir. 1990) (same); see also Romandine v. United States, 206 F.3d 731, 738 (7th Cir. 2000) (expressing agreement with "McCarthy's bottom line" on this point). Finally, we rejected the defendant's arguments that such a conclusion was contrary to the doctrine of dual sovereignty, principles of comity and federalism, and the Full Faith and Credit Clause. Taylor, 284 F.3d at 1151-53.
Reynolds raises two arguments on appeal. First, notwithstanding our decision in Taylor, he asserts that the BOP had an obligation to comply with the state court's determination that Reynolds's sentences should run concurrently with his federal sentence. Second, he asserts that the BOP's denial of his request for nunc pro tunc designation of the Montana prison was arbitrary and capricious, primarily because the BOP based its denial on the historical ...