In a letter addressed to the activist investor, the electronics giant said its entertainment unit, which includes Sony Pictures and Sony Music , was "fundamental" to its future.
It also said its content platform was an asset, now more than ever, as more opportunities to stream to mobiles, Internet and distribution platforms increase.
The letter also indicated its entertainment business was increasing in value, and 100% ownership is crucial to unlocking its full potential and "integral to Sony's strategy."
"Sony's board of directors has unanimously concluded that continuing to own 100 per cent of our entertainment business is the best path forward and is integral to Sony's strategy," the Japanese giant said in a letter to Loeb.
Loeb, whose Third Point LLC fund owns 7% share in Sony, had been calling on the giant to sell up to 20% of its entertainment
division - to unlock value and plough funds back into its ailing electronics unit.
In the letter, Sony CEO, Kazuo Hirai, also reiterated plans to focus on improving its consumer electronics business, which appears to be making a comeback, of late.
Loeb, in turn, said the decision was "good outcome", despite the refusal.
Hirai also promised to release more updates including financial information on its entertainment division.
Company shares fell 5% in Japan and also dropped almost 5% to $20.72 in the US, although rose slightly in after hours trading.