Are oxo-fragmentable plastic bags the same as biodegradable bags?

“Oxo-fragmentable bags are different from Earthnest biodegradable bags. Oxo-fragmentable plastic bags will only break down into smaller pieces over time but will not biodegrade or compost likewise; whereas Earthnest Bio Bags completely breakdown through biodegradation and turn to compost or manure that can be mixed with soil to promote plant growth.”