GameStop's stock concluded the trading week down 19 percent, attributable to continuing investor concerns over Xbox One's used games market solution. The most volatile decline occurred after a report out of the UK this morning claimed GameStop's margins in the pre-owned market would be affected by others taking a cut.

Microsoft sent out the following statement a half hour before trading closed today: "The ability to trade in and resell games is important to gamers and to Xbox. Xbox One is designed to support the trade in and resale of games. Reports about our policies for trade in and resale are inaccurate and incomplete. We will disclose more information in the near future."

GameStop's stock dropped nearly 11 percent today, down $3.90/share to $32.11. At its worst, the company's stock was down to $31/share today. GameStop concluded its previous fiscal year with pre-owned video game products representing $2.4 billion in sales (27.4 percent for the year). If you want a public answer to Microsoft's used game plans, you got nothing on the company that's losing hundreds of millions in value off the situation. [Image: nuttapol yupothong via Shutterstock]