MiniMed (MMED) said late Monday it has closed its initial public offering of 28 million common shares at $20 a share.

The shares debuted on Nasdaq last Friday under the symbol "MMED," the company said.

As of the IPO closing, Medtronic (MDT) owns about 90.03% of MiniMed common stock, the company said.

Net proceeds from the IPO were about $538 million, a portion of which will be allocated for general corporate purposes, and the rest has been used to pay back debt owed to Medtronic, MiniMed said.