Celebrating silver, gold or diamond jubilees
Question

                Some companies or administrations celebrate 25 years since the founding, and they call that a silver jubilee. They also celebrate after 50 years, and call that a golden jubilee, and after 75 years they call it a diamond jubilee and so on. Are these celebrations Sunnah or an innovation?.
Praise be to Allah.
    It is not permissible to hold parties and 
    give gifts and so on, on the occasion of a number of years having passed 
    since the opening of a store, school or any other kind of venture, because 
    this is introducing innovated festivals into Islam, and because it is an 
    imitation of the disbelievers who do such things. It is essential not to do 
    that and to avoid it. End quote. 

    Fataawa al-Lajnah al-Daa’imah, 
    2/261 

    Shaykh Bakr Abu Zayd said in his book 
    ‘Eid al-Yoobeel (Jubilees), p. 25: 

    Celebrating jubilees of various kinds and 
    with various aims is a celebration that has been introduced into the 
    religion (an innovation) and is contrary to the command of the Lord of the 
    Worlds, and is an imitation of the disbelievers and venerating that which 
    they hold sacred. 

    Those who forbid and speak against innovated 
    celebrations -- including celebrating the birthday of the Prophet (blessings 
    and peace of Allah be upon him), the night of the Isra’ and Mi’raaj, the new 
    hijri year, and other innovated celebrations observed by some Muslims which 
    have been introduced by those who seek to misguide others -- their first 
    priority must be to announce the prohibition on celebrating jubilees, 
    whether they are silver, golden, diamond, eightieth, for any length of time, 
    for any place, for any person, for any occasion. Whoever does not do that is 
    confused and contradicting himself, whether he likes it or not, and this 
    comes under the heading of following whims and desires. End quote. 

    And Allah knows best.