https://en.wikipedia.org/wiki/DEC_Alpha says compaq sold "all Alpha intellectual property" to intel in 02001, so probably they haven't made any money from it since then
also though any us patent filed since 01995 expires 20 years after filing, so any us αxp patents filed in the period 01995–02001 have expired already, and us patents filed before 01995 expire 17 years after issuance, so we only have to worry about pre-01995 us patents if first dec and then compaq and intel managed to delay their issuance, lemelson-style, until 02005 or later, which seems extremely unlikely
so αxp is almost certainly already open-source as an isa
dec's implementations are i suppose not open-source though, and casual glancing around on opencores and the like doesn't turn up any obvious candidates
also though any us patent filed since 01995 expires 20 years after filing, so any us αxp patents filed in the period 01995–02001 have expired already, and us patents filed before 01995 expire 17 years after issuance, so we only have to worry about pre-01995 us patents if first dec and then compaq and intel managed to delay their issuance, lemelson-style, until 02005 or later, which seems extremely unlikely
so αxp is almost certainly already open-source as an isa
dec's implementations are i suppose not open-source though, and casual glancing around on opencores and the like doesn't turn up any obvious candidates