Los Angeles-based private equity firm Levine Leichtman Capital Partners has sold its portfolio company Therapeutic Research Center to Colibri Group, a portfolio company of Gridiron Capital.

Thoma Bravo, a leading software private investment firm, has exited it investment in Exostar, a cloud-based secure business collaboration software provider, through a sale to Washington DC-based private equity firm Arlington Capital Partners.

Gilde Healthcare, a private investment firm focused on venture & growth and PE investments in the healthcare sector, has acquired Kosher & Würtz, a German contract manufacturer of precision surgical instruments.

Private investment firm Washington Harbour Partners has acquired SIXGEN Incorporated, a cyber solutions company for the US national security, intelligence, and defence communities, and critical commercial industries.

BV Investment Partners, a middle-market private equity firm focused on the tech-enabled business services, software and IT services sectors, has invested in CallTower, a specialist in cloud-based enterprise-class communications, contact centre and collaboration solutions.

Private equity firm Arctos Partners has acquired a minority stake in AMR Holdings GP Ltd, the owner of the Aston Martin F1 team, in a deal that values the business at $1bn, according to a report by The Financial Times.

Middle-market private equity firm Gemspring Capital has acquired Fenceworks, a fencing installer and distributor serving the some of the largest homebuilders in the US, as well as general contractors and local fencing providers.

Private investment firm Ardian is to sell its stake in imes-icore Holding, a provider of milling and grinding machines for the automated production of dental prosthetics, to EMZ Partners, a European PE firm focused on small- to medium-sized businesses.

Granite Creek Capital Partners, a private investment firm based in Chicago, has acquired NYP Corp, a New Jersey-based value-added packaging manufacturer and distributor focused on the wholesale nursery, agricultural, and industrial markets.