Corporate borrowing has soared to record highs this year. Some worry that the debt binge powering the AI ambitions of Big Tech could spell trouble. Investors have flocked to recent bond sales, but more borrowing poses risks to markets and the economy, sources say. Big Tech firms have led a frenzy of corporate borrowers tapping the bond markets for cash this year, and the trend is catching the eye of Wall Street observers. While commentators have been nervously eyeing huge AI capex all year, it's n ...