Assuming buybacks & dividends are “required”, the unallocated cash flows are matching the capex figure already.
This means additional room to add capex is limited.
Put it in another way, free cash flows after shareholder returns are near 0.
For example, Alphabet got $125bn op. cash flow in 2024, paid $53bn in capex, $62bn in buyback and $7bn in dividend. FCF after shareholder returns is only $3bn, or 2.5% of its operating cash flow.
Meta, with 10% unallocated operating cash flow in 2024, will increase its capex by 50% in 2025. If Meta’s op. cash flow grows 10% in 2025, then FCF after shareholder returns in 2025 is only $3bn, or 3% of its operating cash flow.
Microsoft in calendar year 2024, has $10 billion of unallocated free cash flow. But that should be smaller if looking at its fiscal year 2024.