。
I have five times as many stamps as he does.
Literal
I [topic-は] his [possessive-の] 5-times [attributive-の] stamps [object-を] hold-[state-ている]-[insistence-よ].
X倍 ('X-fold, X-times') is the multiplicative suffix. 彼の5倍 ('his 5-fold' = 'five times his amount') uses の to link. 切手 ('postage stamp'). Simple comparative with a multiplier — a proud collector's boast.