(Bloomberg) -- Some investors are questioning the amount of cash Big Tech is throwing at artificial intelligence, fueling concerns for profit margins and the risk that depreciation expenses will drag stocks down before companies can see investments pay off. Most Read from BloombergTrump’s Military Parade Has Washington Bracing for Tanks and WeaponryNY Long Island Rail Service Resumes After Grand Central FireNYC Mayoral Candidates All Agree on Building More Housing. But Where?Senator Calls for Cl