v3.26.1
Financial risk management - Exposure to credit risk (Details) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Apr. 01, 2023
Disclosure of credit risk exposure [line items]        
Cash and cash equivalents ¥ 9,458 ¥ 8,584 ¥ 10,837 ¥ 7,697
Cash segregated as deposits 50,024 51,655    
Crypto assets held (current assets) 124 370    
Customer accounts receivable 1,422 1,086    
Other financial assets 904 495    
Total financial assets 61,931 62,190    
Total gross carrying amount        
Disclosure of credit risk exposure [line items]        
Total financial assets 61,932 62,190    
Impairment loss allowance        
Disclosure of credit risk exposure [line items]        
Total financial assets 0 0 ¥ 0  
Not credit-impaired        
Disclosure of credit risk exposure [line items]        
Cash and cash equivalents 9,458 8,584    
Cash segregated as deposits 50,024 51,655    
Crypto assets held (current assets) 124 370    
Customer accounts receivable 1,422 1,086    
Other financial assets 904 495    
Total financial assets 61,932 62,190    
Not credit-impaired | Total gross carrying amount        
Disclosure of credit risk exposure [line items]        
Total financial assets 61,932 62,190    
Not credit-impaired | Impairment loss allowance        
Disclosure of credit risk exposure [line items]        
Total financial assets 0 0    
Credit-impaired        
Disclosure of credit risk exposure [line items]        
Cash and cash equivalents 0 0    
Cash segregated as deposits 0 0    
Crypto assets held (current assets) 0 0    
Customer accounts receivable 0 0    
Other financial assets 0 0    
Total financial assets 0 0    
Credit-impaired | Total gross carrying amount        
Disclosure of credit risk exposure [line items]        
Total financial assets 0 0    
Credit-impaired | Impairment loss allowance        
Disclosure of credit risk exposure [line items]        
Total financial assets ¥ 0 ¥ 0