The Star Wars creator was given a 2% stake in Disney upon its purchase of Lucasfilm last year - making him the company's second largest shareholder after Steve Jobs's estate.
Lucas's trust registered the shares with the Securities and Exchange Commission (SEC) on Wednesday (February 6).
Bloomberg notes a sale is not necessarily imminent, but the move does mean that the shares - which number over 37 million - could now be sold at a time of the filmmaker's choosing.
Documents state that the estimated value of each share is $53.78 (£34.36), as based on New York Stock Exchange figures for January 30, 2013.
This puts the maximum value of Lucas's stake in Disney at $1,993,798,414 (£1,273,887,705).
Lucas intends to donate most of the money he received from the sale of Lucasfilm to "philanthropic endeavours".
He established the George Lucas Educational Foundation, which promotes innovation in schools,