43. Are there limits on the amount that third parties can spend on election campaign activities?

Source: 

Article 8, Law on Political Party Financing  2012 (with 2016 amendments)

(BS)

[...] (6) Zabranjeno je davanje dobrovoljnih priloga u novcu ili u formi proizvoda posredstvom trećih lica (posrednika). 
(7) Eventualni dobrovoljni prilozi uplaćeni na račun političke stranke iz nedopuštenih izvora prema st. (1) i (6) ovog člana, kao i iznosi dobrovoljnih priloga koji prelaze iznose utvrđene u članu 6. ovog zakona, te eventualne uplate dobrovoljnih priloga od neimenovanih, odnosno anonimnih izvora, politička stranka dužna je uplatiti u korist budžeta BiH, najkasnije u roku  osam dana od dana primljene uplate, te o tome obavijestiti Centralnu izbornu komisiju Bosne  i Hercegovine.  

(EN)

[...] (6) It is prohibited to make voluntary contributions in money or in the form of goods through third parties (intermediaries).
(7) Any voluntary contributions paid into the account of a political party from prohibited sources under paragraphs (1) and (6) of this Article, as well as voluntary contributions exceeding the amounts established in Article 6 of this Law, and any voluntary contributions from unnamed or anonymous sources, must be transferred by the political party to the budget of Bosnia and Herzegovina no later than eight days from the date of receipt, and the Central Election Commission of Bosnia and Herzegovina must be notified thereof.

Avaliable at:

https://www.izbori.ba/Documents/documents/ZAKONI/Fin_Stranaka/DOC039-bos.PDF