Public Procurement Rules and Regulations: What Every Supplier Should Know

Public procurement is one of the most highly regulated business environments in the world - and for good reason. When governments spend public money, they must ensure that every purchase is fair, transparent, and delivers value to citizens.

For suppliers, understanding these rules isn’t just about avoiding mistakes. It’s about unlocking opportunity. Procurement regulations set the framework for how contracts are advertised, awarded, and managed. 

If you understand how the rules work, you can position yourself as a reliable, compliant supplier - and avoid being disqualified for simple technicalities.

Let’s break down the essentials: where the rules come from, what principles guide them, and how suppliers can stay compliant while competing confidently.

1. The Legal Foundations of Public Procurement

Every public tender you see is governed by a set of laws designed to promote fair competition and protect public funds.

Why procurement law exists

At its core, procurement law is about trust - ensuring that contracts are awarded transparently, without favoritism or corruption, and that suppliers compete on a level playing field. It’s how public buyers demonstrate accountability for taxpayer money.

The key legal frameworks

In Europe, public procurement is primarily governed by three EU directives adopted in 2014:

• Directive 2014/24/EU – Covers most public sector procurement.
  
  

• Directive 2014/25/EU – Applies to utilities such as energy, water, and transport.
  
  

• Directive 2014/23/EU – Governs concession contracts, such as toll roads or public facilities.

Each EU and EEA country then transposes these directives into national law. While the basic principles are the same everywhere, each country can make slight adjustments to fit local administrative systems.

Beyond the EU

Even outside the EU, similar principles apply. The UK, for example, currently follows the Public Contracts Regulations 2015, transitioning to the new Procurement Act 2023. The goal remains the same: open competition and fair treatment.

2. The Core Principles Every Supplier Must Follow

Regardless of location, all public procurement systems share the same foundation - five core principles that guide every tender process.

1. Transparency

All tenders and award decisions must be open and traceable. Buyers must publish opportunities publicly and explain how decisions are made.

For suppliers: Make sure your bids are clear, consistent, and well-documented. Ambiguity can raise red flags.

2. Equal Treatment

All suppliers must be assessed using the same rules. Buyers can’t favor one supplier or adjust criteria mid-process.

For suppliers: Carefully follow the published instructions - don’t assume exceptions or flexibility.

3. Non-Discrimination

Suppliers must not be treated differently based on nationality, size, or location.

For suppliers: Even as an SME, you have the same right to compete as large firms - especially if you meet the qualification criteria.

4. Proportionality

Buyers must only ask for what’s necessary for the contract. Requirements should fit the contract’s value and complexity.

For suppliers: If criteria seem excessive, ask for clarification. You have the right to question disproportionate demands.

5. Accountability

Every decision in public procurement must be justifiable and backed by evidence.

For suppliers: Keep records of all communications and submissions - you may need them for debriefs or appeals.

These principles exist not to make things difficult, but to create fairness - and understanding them helps you recognize when buyers, or even competitors, aren’t playing by the rules.

3. Thresholds and Procedures: Where the Rules Apply

Procurement law applies differently depending on the value of the contract and the type of buyer.

Each country sets financial thresholds that determine which rules apply.

• Above-threshold contracts follow full national or EU procurement regulations.
  
  

• Below-threshold contracts use simplified processes, giving buyers more flexibility.
  
  

The higher the contract value, the more formal the process.. For suppliers, this means:

• Larger contracts require more detailed bids and documentation.
  
  

• Smaller ones may be quicker and more flexible, but still demand compliance with key principles.

Understanding which set of rules applies helps you prepare the right documentation and manage your bidding workload efficiently.

4. Key Compliance Requirements for Suppliers

Compliance is one of the biggest challenges in public procurement - but it’s also one of the easiest areas to control once you’re organized.

Here’s what most public buyers expect you to provide:

• Company registration details – Proof you’re legally established and authorized to trade.
  
  

• Financial statements – Usually the last two or three years of accounts.
  
  

• Tax compliance declarations – Confirmation you have no outstanding tax liabilities.
  
  

• Insurance certificates – Covering liability, professional indemnity, and sometimes cyber risk.
  
  

• Certifications and standards – ISO 9001 (quality), ISO 14001 (environment), ISO 27001 (data security), or industry-specific equivalents.
  
  

• Policy documents – Health and safety, environmental policy, equality and diversity, anti-corruption, and data protection.
  
  

• References or case studies – Evidence of delivering similar contracts successfully.

Missing or outdated documentation is one of the top reasons suppliers are excluded from tenders. A strong compliance foundation saves time, reduces stress, and signals professionalism.

5. Common Pitfalls and How to Avoid Them

Even experienced suppliers fall into compliance traps. Here are the most common mistakes - and how to avoid them:

1. Submitting expired or incomplete documents

Always check expiry dates on insurance or certifications before submission. Create calendar reminders to renew early.

2. Confusing selection and award criteria

Selection criteria assess whether you’re eligible to bid. Award criteria decide who wins. Tailor your content accordingly.

3. Ignoring mandatory ESG or sustainability clauses

Many buyers now require evidence of social value, carbon reduction, or inclusive employment. Don’t skip these sections - they carry scoring weight.

4. Missing regulation updates

Thresholds and national rules change regularly. If you’re not keeping up, you risk using outdated templates or assumptions.

5. Relying on ad hoc document storage

When files are scattered across emails or folders, things get missed. Keep everything in a centralized, shareable compliance library.

Pro tip: Review your compliance pack quarterly - updating policies, renewals, and certificates before they become a problem.

6. How Mercell Helps Suppliers Stay Compliant

Compliance can feel like a full-time job - but it doesn’t have to be. Mercell’s platform is built to simplify the process so you can focus on strategy and delivery, not paperwork.

With Mercell, suppliers can:

• Use built-in compliance checklists to ensure all required documents are in place.
  
  

• Store and reuse key files - certifications, insurances, policies - across multiple tenders.
  
  

• Receive alerts when buyer requirements or thresholds change in your markets.
  
  

• Access guidance on what’s mandatory in each procedure or country.

This level of visibility and automation means fewer disqualifications, faster responses, and stronger bids - all while staying fully compliant.

Compliance as a Competitive Advantage

Public procurement rules may seem complicated, but they exist to keep the system open, transparent, and fair. 

The suppliers who take the time to understand them don’t just stay compliant - they build trust, credibility, and long-term partnerships with public buyers.

Mastering compliance gives you confidence to bid more often, with fewer mistakes and better outcomes. 

And with Mercell’s tools, you can manage compliance seamlessly - making sure you’re always ready when the next opportunity appears.