Goldman Sachs downgraded its rating on Clorox shares to sell from neutral on Wednesday, casting doubt over the company's ability to perform through the fourth quarter of this year.

"We see unsustainably high relative valuation for Clorox ... compounded by" risk to its earnings, Goldman Sachs wrote in a note to investors.

Clorox stock closed Wednesday at $129.53 per share, down 4 percent. Shares of Clorox have fallen nearly 13 percent this year.

"We believe organic sales are likely to decline as volume weakens due to price increases," the firm said.