Are subcontracting opportunities being posted after the Prime Contractor has already been awarded the contract?

Hello Readers,

So my current situation is searching for an outsourcing firm that hires employees within the federal contracting business.

I am looking to form my team who will be doing subcontracting work for Prime contractors.

Are subcontracting opportunities being posted after the Prime Contractor has already been awarded the contract?

Should you require any clarification let me know and I will be more than happy to explain.

I am looking forward to your input.

Thank you