Public procurement evaluates bids in phases. Phase one — administrative and mandatory compliance — happens before anyone looks at your price or your technical proposal. A bid that fails phase one is disqualified regardless of how competitive it would otherwise have been. Industry estimates put SMME disqualification at this stage as high as 90%, and the causes are almost always the same handful of preventable issues.
In rough order of frequency: an expired or missing CSD registration; a lapsed SARS Tax Compliance Status PIN; a missing or incorrectly completed mandatory SBD/MBD form (most often SBD 4 / MBD 4, the declaration of interest, left blank rather than explicitly completed as "none"); an expired B-BBEE certificate or affidavit; and — for construction and technical tenders — a CIDB grading that doesn't meet the stated minimum in the correct class.
Almost none of these are pricing or capability failures. They are document-currency failures — a real registration or certificate that existed and was valid at some point, but had quietly expired by the time it was needed. The businesses that consistently get past phase one are not necessarily the ones with the best compliance documents; they are the ones who check document validity against the tender's closing date before submitting, not after.