US-listed drilling rig owner Diamond Offshore has raised $550m from the bond market in a further sign of warming investor interest in the offshore drilling market.

The seven-year senior secured second lien notes have a coupon of 8.5% and are due to mature on 1 October 2030, the company said.

The offering was upsized to $550m from the original offering size of $500m on the back of strong interest from investors.