The first essential steps toward implementing the integrity pact (IP) in Bulgaria were made between 2004 and 2011 when Transparency International Bulgaria set up an independent civic monitoring initiative to increase transparency and accountability of the contracting project for the construction of the Trakia highway.

The implementation of the contracting project had begun in 2004, and the contracting authority initially planned to award the tender for construction to a specific contractor without any competitive procedure. Following numerous media reports and backlash from several political leaders, policy experts, and ordinary citizens over the deal, in late 2004, TI Bulgaria carried out an independent review of the transparency and legal appropriateness of the tender. They found the tender faulty regarding legal appropriateness, competition, and value for money and approached national and European Union (EU) authorities calling for halting the tender and reconsidering its design.

Finally, in 2009, a decision was made to change the tender design and apply a competitive procedure. The Ministry of Regional Development and Public Works invited TI Bulgaria to carry out independent monitoring of the process. This first IP took the form of a bilateral cooperation agreement where participants in the tender procedure and contractors were not invited to join and served as an important starting point for the development of the Bulgarian IP model (see next section).

One of the most prominent achievements of this first civic monitoring initiative was the reduction of the expenditure for construction works. The 2005 contract cost estimate was €1.5 billion, while the final cost of the construction in 2011 was €247 million.

Based on the above-mentioned civil monitoring experience, several expert assessments, sociological research, comparative studies, and legal analyses, TI Bulgaria developed an integrity pact (IP) model tailored to the country's context and legislative framework.

The Bulgarian model consists of a tripartite agreement between the contracting authority (CA), the independent observer or monitor, and the bidders. Under the IP, the parties agree to refrain from corruption, report irregularities, provide the monitor full access to relevant documents, meetings, and communication, and confidentially answer its questions in a timely manner.

In addition, both the contracting authority and the bidders are required to provide the monitor with a list of all the natural and legal persons taking part across all phases of the public contracting procedure, as well as planned and actual expenditures for external staff (for example, consultants) involved in the preparation, participation, and execution of the contract. Both parties must notify the monitor of potential changes promptly.

The independent monitor oversees the correct implementation and compliance with the IP by analysing and vetting documents produced during the procedure, observing working meetings and on-site inspections, and conducting sociological research - including surveys and interviews with participants.

Notably, the signature of the IP by bidders is not mandatory, but the model emphasises positive incentives for them to join the agreement. This is done through a “whitelist”, which includes the names of all the tenderers and contractors and specifies those who have signed the IP and those who have been excluded from the list due to breaches of the IP. Contracting authorities are required to publish and promote the whitelist on their website and exchange information with foreign contracting authorities upon request. To ease the burden of this process, TI Bulgaria keeps a centralised whitelist on its website, which contracting authorities can link to their website.

In 2012-2013, the Bulgarian IP model was piloted in three public contracting projects carried out by three different institutions:

• planning and construction of a section of the Struma motorway (€102 million), managed by the Road Infrastructure Agency and the Ministry of Regional Development
• reconstruction of homes for children's medical care in Sofia (€105 million), managed by the Ministry of Health
• creation of a national system for electronic data exchange of social security information, managed by the Ministry of Labour and Social Policy

A 2013 report by TI Bulgaria provides a detailed evaluation of the application of the Bulgarian model, including fulfilment of IP commitments by CAs and bidders (deemed to be satisfactory) and impacts of the application of the tool. According to TI Bulgaria, the most positive results were observed in increased transparency about the actions of main actors across all stages of the procurement procedures, as well as more effective control over the preparation, awarding, and execution of public contracts.

In addition, TI Bulgaria noted that the IPs had a robust disciplinary effect on the actions of everyone involved from the side of the CA and contractors and that they allowed for the early identification and neutralisation of potential problems, with the monitor playing a decisive role in solving issues of communication and interaction between the parties.

The latest integrity pact (IP) in Bulgaria was implemented in the context of the EU-wide programme to pilot IPs to safeguard EU funds. As part of the programme, TI Bulgaria monitored a €128 million contracting project to design and construct a 2km tunnel along the Struma motorway, near the village of Zheleznitsa, carried out by the Road Infrastructure Agency. The IP, which covered all phases of the procedure, was signed in 2017, and TI Bulgaria’s monitoring team included legal, social, and engineering experts.

The monitoring work, which only began in 2019 due to delays in the planning phase, brought benefits to all stakeholders. The monitor helped the contracting authority develop a new model for the regular provision of information on the procurement and to identify and remedy financial, security, and execution risks in the implementation of the contract. The monitor also helped contractors develop a system to promptly respond to the contracting authority's requests for clarifications and copies of documents such as the register of order and test certificates.

To encourage community involvement, TI Bulgaria also designed and launched an online reporting tool called Tunnel.report, which allowed affected communities and the general public to submit questions, share observations and concerns, anonymously report potential breaches of the contract and other irregularities, and even upload images and geo-references. The monitor collected all the contracting authority’s responses and published them online.