Investors looking to shore up their portfolios in this volatile market should look into buying companies with strong free cash flows, according to Morgan Stanley. Free cash flow theoretically measures the amount of cash a business will have left after paying operating expenditures. Morgan Stanley found that in the last 12 months, operating cash flows have increased nearly 5% on the year to $2.2 trillion, and capital expenditure spending increased by more than 18% to $786.1 billion. This is important because it shows what companies may have a better financial foundation in place if the economy does fall into a recession, wrote strategist Todd Castagno in a Friday note. Investors have been wary of a U.S. recession following two consecutive quarters of negative gross domestic product and continued high inflation that’s spurred aggressive interest rate hikes from the Federal Reserve. Markets have been choppy all year but had a particularly dismal September, where the S & P 500 hit a new bear market low. “Self-financing companies with strong FCF may be better able to weather a prolonged storm, deploying capital effectively and seizing upon opportunities that come along the way,” Castagno wrote. “Cash rich companies with high free cash flow yields should also have better downside protection, while providing longer-term upside potential if management is able to deploy cash effectively.” Morgan Stanley also made a list of companies with strong free cash flows ranging from 10% to nearly 30% as ideas for investors, though the bank notes that individual assessment is warranted before buying any of the names. Most names on the list are energy or materials companies such as Marathon Oil and Steel Dynamics. There are also industrial names such as Manpower Group , health care companies such as Jazz Pharmaceuticals and Info Tech names like Western Union Company . The year-to-date performance of names on the list has been varied. Energy names such as Marathon Oil and HF Sinclair company have surged this year, up more than 40% and 65%, respectively. But other names on the list are trading at more of a discount. Dow, for instance, is down about 18% this year. Westlake Corporation has also shed more than 11%. Overall, however, the group has had a solid performance. So far this year, the group has outperformed the S & P 500 by roughly 21%, according to Morgan Stanley. — CNBC’s Michael Bloom contributed to this report.