The Nikkei, Japan's largest business paper, and Kyodo News Agency both report a deal may be struck by the end of this year.
Sanyo was rescued in 2006 with a $3 billion investment by Goldman Sachs, Sumitomo Mitsui Banking and Daiwa Securities, which became the company's biggest shareholders.
The cash from a share sale to Panasonic would be helpful to the banks, which are feeling the effects of the global financial slowdown.
A deal would let Panasonic merge Sanyo's large battery operations with its own, as well as gain possession of Sanyo's solar panel business and enter the quickly growing industry.