Microsoft chose Scotland for a research project because the Welsh Government was too slow to a request for £1m, a former government advisor has said.
A huge data centre was sunk off the Orkney coast instead of Pembrokeshire.
Microsoft said it decided based on other factors and the Welsh Government said it responded “swiftly” to requests that could bring in good-quality jobs.
But David Williams said the “more than winnable” deal was lost because a decision was not made within 48 hours.
Mr Williams was chairman of the energy and environment sector panel, and ran a company that wanted to design and power the data centre in Pembrokeshire.
He said Microsoft asked the Welsh Government for money to make the deal happen, but did not get an answer quickly enough.
“Microsoft needed £1m investment from the Welsh Government to make the Welsh bid competitive with another government.
“The decision was needed within 48 hours. But the Welsh Government couldn’t do it because the systems did not exist to make a decision like that.”
A Microsoft spokeswoman said the decision was based on “a data-driven, fact-based evaluation to determine the best overall site and solution for the project”.
And a spokeswoman for the Welsh Government said it would respond quickly to applications from businesses looking to bring investment.
She added: “However, we should never lose sight of the fact that this is taxpayers’ money and there needs to be a transparent and rigorous process of due diligence to ensure all of our funding is being used responsibly and proportionately.”