Participating in pension plans other than those organized by the government is a kind of gambling. But if participation is compulsory, there is no sin on you.

Lottery is another name for gambling which is haram according to the Quran and Sunnah, and the consensus of the scholars.

Gambling is haram because Allah has forbidden it. Gambling destroys families and causes the loss of wealth through haram means. Gambling results in enmity and hatred among the players. Gambling turns people away from the remembrance of Allah.