Beverly Hills firm Platinum Equity announced Monday that it has acquired Ying Shing Enterprises Ltd., a Hong Kong injection molding and metal stamping company. Terms of the deal were not disclosed.

Century City firm Breakwater Investment Management announced Tuesday that it co-led a $12 million follow-on equity investment in one of its portfolio companies, Portland, Ore., radio station operator Alpha Media Holdings.

Westwood firm Aurora Capital announced Thursday that it has completed the purchase of Restaurant Technologies Inc. in Minneapolis, which provides cooking-oil disposal and management services. Terms of the deal were not disclosed.