This depends on how much control you have over the funds. If it's a personal retirement account you can access or liquidate at will, even with a penalty, most scholars treat it as your zakatable wealth: include its current value, and if it's invested in shares, apply the same investment logic used for stocks. If it's an employer-managed pension you cannot access, withdraw, or control until retirement, a qualifying age, or resignation, the more accepted contemporary view is that zakat isn't due while the funds remain locked away and outside your ownership and disposal, since zakat requires full disposal-level ownership (tasarruf). Once you actually receive a lump sum or begin drawing payments, zakat becomes due on what you receive and retain, calculated going forward like any other cash from that point. A minority of scholars hold the stricter position that zakat accrues silently every year the funds exist, to be paid retroactively once received, though this is difficult to apply in practice. Given the genuine difference of opinion, it's worth consulting a knowledgeable scholar familiar with your country's specific pension system.
Q&A · Zakat
Do I need to pay zakat on money in my retirement or pension account?
References
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.