As traders get ready to cap a rough week, month and third quarter, Goldman Sachs is giving clients a way to go on offense and protect their portfolio. This week — the last one in September — the S & P 500 fell to its lowest intraday level since 2020 and closed at a new low for 2022, and the 10-year U.S. Treasury yield briefly topped 4%, the highest level since 2008. With that in mind, Goldman highlighted 21 stocks "where put options are attractive, based on limited downside support, to hedge a deteriorating fundamental environment." A "put" is a type of options contract investors can purchase if they think a stock will go down in the near future. Puts give investors the right to sell a set number of shares at a specified price by a certain date. "Our studies have shown that puts on stocks with low free cash flow are systematically undervalued," Vishal Vivek, an options strategist at Goldman Sachs, said in a note this week. "For investors looking to protect their portfolio, we identify names with limited fundamental downside support based." Goldman focused on sell-rated stocks in its non-financials coverage universe, weeded out the companies with less than $3 billion in market cap, and then highlighted the remaining names with the lowest free cash flow yield (3% and under). "We find low FCF yield stocks have less downside support than high FCF stocks, yet put prices systematically underprice the downside risk," Vivek said. Here are 10 of the stocks: About half of the named stocks have less than 0% free cash flow yield, including U.S. Steel , Dominion Energy , Mister Car Wash and ConEd . Roblox is also on the Goldman list. The gaming platform has free cash flow yield of 1% as does Align Technology . On the other end of the scale, Netflix and Boston Beer have 3% FCF yield while Intel 's is 2%. — CNBC's Michael Bloom contributed to this report.