28 C.F.R. § 2.35 : Judicial Administration — DEPARTMENT OF JUSTICE — PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS, YOUTH OFFENDERS, AND JUVENILE DELINQUENTS — UNITED STATES CODE PRISONERS AND PAROLEES — Mandatory release in the absence of parole

(a) A prisoner shall be mandatorily released by operation of law at the end of the sentence imposed by the court less such good time deductions as he may have earned through his behavior and efforts at the institution of confinement. If released pursuant to 18 U.S.C. 4164, such prisoner shall be released, as if on parole, under supervision until the expiration of the maximum term or terms for which he was sentenced less 180 days. If released pursuant to 18 U.S.C. 4205(f), such prisoner shall remain under supervision until the expiration of the maximum term or terms for which he was sentenced. Insofar as possible, release plans shall be completed before the release of any such prisoner.
(b) It is the Commission's interpretation of the statutory scheme for parole and good time that the only function of good time credits is to determine the point in a prisoner's sentence when, in the absence of parole, the prisoner is to be conditionally released on supervision, as described in subsection (a). Once an offender is conditionally released from imprisonment, either by parole or mandatory release, the good time earned during that period of imprisonment is of no further effect either to shorten the period of supervision or to shorten the period of imprisonment which the offender may be required to serve for violation of parole or mandatory release.
(c) A prisoner committed under the Youth Corrections Act must be initially released conditionally under supervision not later than two years before the expiration of the term imposed by the court.
(d) If the Commission orders a military prisoner who is under the Commission's jurisdiction for an offense committed after August 15, 2001 continued to the expiration of his sentence (or otherwise does not grant parole), the Commission shall place such prisoner on mandatory supervision after release if the Commission determines that such supervision is appropriate to provide an orderly transition to civilian life for the prisoner and to protect the community into which such prisoner is released. The Commission shall presume that mandatory supervision is appropriate for all such prisoners unless case-specific factors indicate that supervision is inappropriate. A prisoner who is placed on mandatory supervision shall be deemed to be released as if on parole, and shall be subject to the conditions of release at §2.40 until the expiration of the maximum term for which he was sentenced, unless the prisoner's sentence is terminated early by the appropriate military clemency board.

28 C.F.R. §2.35

42 FR 39809, 8/5/1977, as amended at 50 FR 46283, 11/7/1985; 67 FR 67792, 11/7/2002; 68 FR 16720, 4/7/2003