The sleep apnea developer, backed by Medtronic and Johnson & Johnson, floated at the top of its range before seeing its stock rise 56% on the first day.

Inspire Medical Systems, a US-based sleep apnea device developer spun out of medical device maker Medtronic, raised $108m in an initial public offering on the New York Stock Exchange yesterday.

The offering consisted of 6.75 million shares priced at $16 each, the top of its $14 to $16 range. The underwriters have a 30-day option to buy more than 1 million more shares, which would lift the IPO to just over $124m.

Founded in 2007, Inspire Medical has developed what…