Penal Code section 2933.6, limiting credit for a validated prison gang member in segregated housing, does not violate the prohibition against ex post facto laws. Following his November 5, 2008, conviction for grand theft and imposition of a prison sentence, petitioner was placed in the prison segregated housing (SHU) because he was a validated prison gang member. On January 22, 2010, prison officials informed inmates that effective January 25, 2010, Penal Code section 2933.6, subdivision (a) made validated gang members ineligible to earn conduct credits as long as they were in the SHU. The appellate court found that there was no ex post facto violation resulting from the denial of conduct credits to petitioner. If the statute constituted punishment, there was no ex post facto violation because it did not impose punishment for petitioner’s commitment offense. Instead, it imposed punishment for his continued gang conduct after the effective date of the statute, and the statute thus was applied prospectively.