Bai al-Inah is a sale-and-buyback arrangement used in Islamic finance. A bank sells an asset to a customer at one price (say, $10,000 cash), then immediately buys it back from the customer at a higher price ($12,000) payable in installments.
The customer gets $10,000 cash immediately and repays $12,000 over time. The $2,000 difference is the bank's profit. The asset never actually changes hands in any meaningful way — it is just a legal mechanism to generate cash financing.
Bai al-Inah is controversial in Islamic finance. Malaysian scholars generally accept it, but most Middle Eastern scholars reject it as a disguised form of interest (riba). Many prefer Tawarruq as an alternative.