Look out for companies that report consistent profits but also a substantial rise in gearing, which would indicate negative FCF.
Receivables and/or inventories rise even faster than increasing sales
This is usually the case when companies report increasing sales but where receivables and/or inventories rise even faster.
If a company's receivables grow at a much faster rate than revenue, it will suffer net cash outflows, which have to be funded with increasing debt (or cash calls). It can continue to report steady profits for many years - even as the company is being crushed by mounting debt and interest expenses. Investors who are fixated on earnings would not realise the looming issue until it is too late.
Paying dividends in excess of cash flow from operations
Companies that pay dividends in excess of cash flow from operations may also warrant a red flag.
This is the danger when management's interest are not always aligned with that of shareholders. The fact is that management remuneration/incentives are usually based on profitability and share price gains, which encourages short-termism and risk-taking, including using leverage to boost earnings. Anecdotal evidence shows that high dividends/share buybacks tend to lead to higher share prices.
Indeed, sometimes not all shareholder's interests align either. Some are short term, preferring dividends/share buybacks while longer-term-minded investors would prefer companies to conserve cash for future opportunities and/or pay down their debts.
Borrowing to invest in productive assets
Companies necessarily reinvest for the future, funded with internally generated funds and/or borrowings and equity cash calls. Borrowing to invest in productive assets that will generate future cash flows is perfectly fine - as long as the increased risks that come with it are understood and properly taken into consideration.
Company with less debts is less risky and better positioned
Company that pay off its debts would be better positioned to withstand any unexpected economic and financial shocks - thereby making it the safer investment. It would be better able to capitalise on future opportunities - for example, mergers and acquisitions, relative to its competitors which large debts, thanks to its stronger balance sheet.
Conclusions
There will always exist a trade-off between risks and rewards. It is important to analyse both aspects in tandem.
There is nothing wrong if you choose to go for the higher returns, provided you also understand the risks and can stomach the potential losses.
Some investors are risk takers, others are more risk-averse, but the smartest investors make informed decisions.