27. Are there provisions requiring donations to go through the banking system?

66. [...] The receipt issued by a political party shall openly state that the donation or donations belong to the donor or his authorized representative or proxy. Political parties shall not accept donations in the absence of such a document. (Annex sentence by Article 181 of Law 6111, dated 13 February 2011) An income statement shall not be required for the donations deposited to the bank accounts opened in the name of a political party.[...]
Source: Article 66, Law on Political Parties, 1983 (amended 2018)

Above certain amount, donations (2,000,00 TRY in 2018) are deposited at the bank accounts of the presidential candidates. Donations below this upper limit are received in return of a receipt which is designated by the Circular of the Supreme Board of Election.
Source: Article 14(4), Law on Presidential Election, 2012
Source: Circular of the Supreme Board of Election Indicating the Procedures and Principles Concerning the Aids and Donations to be Made to the Presidential Candidates and Their Asset Declaration (in Turkish), 2018

In case of donation through bank account, there is no need to attach an income statement.