Look no further than Big Tech's free cash flow concerns as the primary culprit for the bull market in stocks broadening out to other sectors. Free cash flow has come under increasing pressure as tech giants spend aggressively on capex to support their AI ambitions. Concerns that Big Tech companies are spending too much — and the likelihood that they will continue and weigh down cash flow — have caused a noticeable broadening out in the stock market. Down goes free cash flow! The bottom line: With free cash flow outlooks likely to remain subdued among prominent tech names in the medium term, it's plausible that the broadening in the market will stretch on.