In plain English
FAR 52.232-14, Notice of Availability of Progress Payments Exclusively for Small Business Concerns, is a contract clause prescribed at FAR 32.502-3(b)(2), most recently dated Apr 1984. The complete official text is reproduced below, verbatim, from GSA's published FAR source files.
Its text contains no sentence requiring insertion into subcontracts; see the flowdown section below for what that does and does not mean.
Does it flow down to subcontracts?
No flowdown mandate found in the clause text
We scanned the full clause text and found no sentence directing the contractor to insert this clause into subcontracts. That is a statement about the text, not legal advice: a prime contractor may still flow terms down contractually, an agency supplement (DFARS, VAAR, …) may add requirements, and clauses listed below (if any) may order this clause into subcontracts from the outside.
Where it's prescribed
As prescribed in 32.502-3(b)(2), insert the following provision in invitations for bids if it is anticipated that (a) both small business concerns and others may submit bids in response to the same invitation and (b) only the small business bidders would need progress payments:
Prescribing reference: FAR 32.502-3(b)(2).
The official text, verbatim
As prescribed in 32.502-3(b)(2), insert the following provision in invitations for bids if it is anticipated that (a) both small business concerns and others may submit bids in response to the same invitation and (b) only the small business bidders would need progress payments:
Notice of Availability of Progress Payments Exclusively for Small Business Concerns (Apr 1984)
The Progress Payments clause will be available only to small business concerns. Any bid conditioned upon inclusion of a progress payment clause in the resulting contract will be rejected as nonresponsive if the bidder is not a small business concern.
(End of clause)