The French group said the Californian company will join its Packaging Division and the deal continues its intercontinental growth.
Thoro Packaging is a producer of custom holding carton packaging from its 54,000 square foot facility in Corona, California and has a 38,000 square foot finished goods warehouse.
The firm said the latest trend in design is shape differentiation.
It serves customers in the pharmaceutical, health and beauty, food confections and other consumer product markets.
Thoro Packaging provides creative packaging for the confectionery industry from simple tuck-end boxes to custom specialty packaging.
Additional US presence
Autajon Group said it brings an additional opening on the American market.
Autajon Packaging USA is a business partner of Lindt & Sprüngli USA.
The company is a manufacturer of folding cartons, labels, set-up boxes and POS for various market sectors such as wine and spirits, confectionery and food specialties.
Production capacity consists of 34 subsidiaries, based in Europe, Asia and three in the US and the group employs 4,500 people.
The firm said the right choice of substrate, inks, varnishes, laminations, foil-blockings and embossings is important for confectionery packaging.
Mesirow Financial acted as the exclusive financial advisor to Thoro Packaging on the sale.
Janet Steiner, CEO and president of Thoro Packaging, said: "Mesirow Financial was instrumental in conducting an effective and competitive transaction process that ultimately paired Thoro Packaging with an ideal strategic partner."
Mesirow Financial is an active advisor in the paper, plastics, packaging and specialty printing sectors, having completed more than 100 transactions in recent years.
Bill Hornell, managing director of Mesirow Financial's investment banking group, said, "We believe that this strategic combination will provide Thoro Packaging with a global platform to expand and continue delivering exceptional service and quality products to its customers."