Mulco was a watch brand established in 1931 by Mühlmatter & Grimm of La Chaux-de-Fonds. It remained active through 1995, when a new company, Mulcor Sàrl, was established by the Müller family to supply watch components.

Mühlmatter & Grimm was registered on November 29, 1919 by Edouard Mühlmatter of Spiez and Paul Grimm of Trubschachen in Berne. The company specialized in watch finishing (“terminage”) and was based initially on Rue Numa-Droz 155 in La Chaux-de-Fonds.

In the 1920s, Mühlmatter & Grimm were offering finished movements from A. Schild, Felsa, Kurth, and Essor for watchmakers. By 1927 the company offered a variety of compact round and shaped movements for the burgeoning wristwatch market. Over time the company focused more on A. Schild and FHF movements, and by 1931 had relocated to Rue Régionaux 11.

Mühlmatter & Grimm faced difficult times in the Great Depression and was nearly insolvent by 1931. Mühlmatter left the company on August 29, 1931, and Grimm registered the Mulco brand on October 2. Thanks to investment of 40,000 francs, the company was re-launched on November 11, 1931 as Montres Mulco, under the direction of Robert Müller-Caccia of Unterembrach, with Paul Grimm no longer involved.

One of Müller's first actions as head of Mulco was to purchase Automatic EMSA, which owned the novel automatic winding mechanism invented a year earlier by Eugene Meylan. This independent unit could transform any 8.75 ligne hand-winding movement to automatic, and was the basis for the first commercially successful automatic watches from Glycine. Meylan, a serial entrepreneur and inventor, had founded and sold “La Glycine” in the 1910s and had just recently created Automatic EMSA to commercialize his automatic mechanism.

After acquiring Automatic EMSA on December 8, 1931, Müller asserted the rights to the mechanism. He offered to license it to others, drawing the ire of Pretto Watch, who had licensed the design from Meylan and produced it for Glycine. The situation exploded in 1933 as Glycine found a broad market for their new automatic watch, even as Mulco offered a similar unit they saw as infringing. With the help of Georges Henry, manager of Gigantic and Pretto and founder of Nanda and Ilosa, Glycine and Pretto counter-sued. Under threat of legal action, Automatic EMSA was unable to license the design to others and ultimately failed on January 9, 1936.

Undeterred, Müller pressed forward and re-established Mulco as World War II neared a close. The company offered dozens of watch models, including popular designs with chronograph and automatic movements. A new technical director, Gérard Mathez, helped set the company on better footing after 1946 and Mulco expanded in the post-war period.

Müller saw opportunity in South America and expanded Mulco there, even as he continued to build the company's presence in Europe. In the 1960s, Mulco was part of the sports watch trend, producing super compressor dive watches.

Mulco did not join any of the emerging watch groups in the 1960s and 1970s and the brand was no longer active globally in the 1970s. The company remained at Rue de Régionaux 11 in La Chaux-de-Fonds from 1930 through the 1970s, seeing companies like Henry Sandoz, Girard-Perregaux, Rode Watch Co., and Degoumois & Co. come and go over the decades.

The Mulco brand was retired in April 1995 by Lucien Müller, with a new company Mulcor Sàrl taking its place. The company became a producer of watch components and the Mulco brand would not be used again.

• Eugène Meylan, Glycine, and the Fight Over the First Automatic Watch