However, the bankruptcy rate in agriculture actually declined 5% compared with 2006.
The number two sector is retail trade (16% of insolvent companies last year), which is 6% more than in 2006.
Surprisingly, the construction sector came third. The reason is that construction activities on the Black Sea Coast and in the mountain resorts are relatively low paid.
Other sectors with significant numbers of bankrupting companies are transport, storage services, finance, insurance and consultancy.
The number of companies filing for insolvency jumps 31% compared with 2006, which is not much compared with the total number of registered and operating companies in the countries.
Koface Bulgaria has been following this statistics since 2004.
According to the research, the least risky sectors in Bulgaria are chemical production and the pharmaceutical business, whose products are primarily exported.
Koface Bulgaria expects bankruptcy filing from construction companies to continue to be strong this year.
Three of last year's most prominent close downs were those of Zlatni Piasatsi Travel (tourism), Mlechen Ray 99 (ice cream maker) and Termosystems Complect (machine manufacturer).