If you apply for finance at an Islamic Financial Institution (IFI), you will usually be asked to sign a unilateral promise/undertaking to purchase the particular asset from the IFI once they have purchased the asset and subsequently have ownership and possession over it.
If you subsequently refuse to purchase the asset from the IFI after it has purchased it from the market, you can become liable for any actual cost incurred by the IFI. For example, if because of your promise/undertaking the IFI had purchased the asset for 100 and can only sell it in the market for 90, you would be liable to pay the 10 difference. However, you would not be liable to pay the IFI for any opportunity cost incurred e.g. if the IFI was meant to sell the asset to you for 110, but could only sell it in the market for the same price it purchased it for i.e. 100, you would not be liable for the difference of 10.
Attached is an excerpt from 𝘼𝘼𝙊𝙄𝙁𝙄 𝙎𝙝𝙖𝙧𝙞𝙖𝙝 𝙎𝙩𝙖𝙣𝙙𝙖𝙧𝙙 𝟰𝟵 𝙤𝙣 𝙐𝙣𝙞𝙡𝙖𝙩𝙚𝙧𝙖𝙡 𝙖𝙣𝙙 𝘽𝙞𝙡𝙖𝙩𝙚𝙧𝙖𝙡 𝗣𝙧𝙤𝙢𝙞𝙨𝙚. You can refer to the full Shariah Standard for more information. Please note that not all Shariah Committees agree with the concept of binding unilateral promise/undertaking.
