On the company's PlayXBLA site, the company revealed that the trademark for the Killer Instinct series has been renewed.
"With all due respect to our friends in the media who like to frequent trademark sites, we thought we'd break this one ourselves," The PlayXBLA blog said.
"Our legal eagles have authorized us to say: 'We have either renewed or refiled a trademark application in various jurisdictions.'"
Typically a trademark renewal is not announced, making it appear that Microsoft is teasing an XBLA port of the original arcade game, a reboot or new title in the Killer Instinct series.
Killer Instinct first released in arcades in 1994. The fighting game was developed by Rareware, which was purchased by Microsoft in 2002.
Watch video of the original Killer Instinct below: