All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
It is permissible under Sharee‘ah to deduct a certain part of the salary and invest it according to the teachings of Islam, provided that you agree. However, it is impermissible to deduct the sum against your will or to invest it in unlawful transactions or projects, such as selling wine, pork, Riba-based transactions and so forth.
With regard to the request to join the savings fund according to the Islamic system, you are entitled to ask the concerned authorities to invest the money of the participants in lawful projects according to the Islamic teachings. Every Muslim has the right to invest his money according to his beliefs and religious teachings. Rather, he is required to do so under Sharee‘ah.
Allaah Knows best.