Sony's shares tanked over 8 percent on Tuesday after the Japanese electronics giant said it was looking to raise billions of dollars through a share and convertible bond issue.
The company said on Tuesday that it expected to raise 440 billion yen ($3.6 billion) to boost production and research in its image sensor business. The corporate bonds will be used to redeem outstanding bonds upon maturity and "repay long-term indebtedness as it comes due".
The share sale is the company's first since 1989.
Sony shares closed down 8.26 percent in Tokyo.
CEO Kazuo Hirai has been slowly turning around the struggling giant and has axed thousands of jobs and restructured the business to focus on lucrative areas such as image sensors, games and entertainment.
So far this year, shares are up 40 percent.
Sony said earlier in 2015 that it expected operating income to more than quadruple in the year ending March 31 2016, as it turned more bullish on its outlook.