Allegro MicroSystems first filed to go public in 2007, then pulled the deal a year later. It took thirteen more years to try again. The company makes chips that sense magnetic fields, which lets a car know the angle of a steering shaft or the speed of a wheel. It shipped more than a billion units a year to over 10,000 customers. When it finally listed in October 2020, electric cars were making those chips more valuable.

Born From Sprague

Allegro was formed in 1990 when Sanken Electric, a Japanese power electronics company, bought the semiconductor division of Sprague Electric. It became a specialist in magnetic sensor chips and in power chips that drive small motors. Cars became its biggest market. A modern vehicle uses sensors to track pedals, seats, wipers, and motors. The bet was that every new electric motor in a car would need an Allegro part.

The Second Attempt Works

Allegro filed an S-1 in August 2007 and withdrew it in August 2008, as the financial crisis closed the IPO window. Its second offering priced at $14 a share in October 2020, and Allegro raised $350 million. Its shares listed on Nasdaq under ALGM. Sanken remained a major shareholder after the deal. Electric cars and factory automation then lifted demand for its parts. Allegro still trades on Nasdaq as ALGM.

Cover: Village Violinist, Anders Zorn. Art Institute of Chicago, public domain. Chosen for a village violinist (allegro, the quick tempo).