In short: An occupational pension fund is a pension fund linked to a job or an employer, into which contributions are paid for the workers so that they receive a supplementary pension.
Simply put: In some countries employers pay into a workplace pension; in others it is compulsory for certain hazardous or heavy jobs. In the EU, such funds (IORPs) are governed by Directive (EU) 2016/2341, which requires a free annual Pension Benefit Statement for members.
Example: A worker in category I labour has insured income of €1,000. The employer pays 12% = €120 a month into the fund; for category II it would be 7% = €70.
Watch out: If the contribution is paid by the employer, check in your statement that it arrives every month.
Example: Bulgaria — The "professional pension fund" (PPF) is compulsory for people working in category I and II labour (Social Security Code, Art. 127(2)). Contributions are 12% (category I) and 7% (category II) (Art. 157(1)(2)) and are paid entirely by the employer (Art. 157(4)).
Check in your country — Ask your employer or the scheme whether you are in a workplace pension, who pays in, and where your annual statement comes from.
Source: Directive (EU) 2016/2341 (IORP II), Art. 38 — https://eur-lex.europa.eu/eli/dir/2016/2341/oj · Social Security Code (Bulgaria), Art. 127, 157 (in Bulgarian) — https://lex.bg/laws/ldoc/1597824512