v3.25.2
Financial risk management - Exposure to credit risk (Details) - JPY (¥)
¥ in Millions
Mar. 31, 2025
Mar. 31, 2024
Apr. 01, 2023
Mar. 31, 2022
[1]
Disclosure of credit risk exposure [line items]        
Cash and cash equivalents ¥ 8,584 ¥ 10,837 [1] ¥ 7,697 [1] ¥ 17,704
Cash segregated as deposits 51,655 59,256 [1] 40,936 [1]  
Crypto assets held 370 817    
Customer accounts receivable 1,086 719 [1] 439 [1]  
Other financial assets 495 651    
Financial assets 62,190 72,280    
Gross carrying amount        
Disclosure of credit risk exposure [line items]        
Financial assets 62,190 72,280    
Impairment loss allowance        
Disclosure of credit risk exposure [line items]        
Financial assets 0 0 ¥ 0  
Not credit-impaired        
Disclosure of credit risk exposure [line items]        
Cash and cash equivalents 8,584 10,837    
Cash segregated as deposits 51,655 59,256    
Crypto assets held 370 817    
Customer accounts receivable 1,086 719    
Other financial assets 495 651    
Financial assets 62,190 72,280    
Not credit-impaired | Gross carrying amount        
Disclosure of credit risk exposure [line items]        
Financial assets 62,190 72,280    
Not credit-impaired | Impairment loss allowance        
Disclosure of credit risk exposure [line items]        
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 0 0    
Customer accounts receivable 0 0    
Other financial assets 0 0    
Financial assets 0 0    
Credit-impaired | Gross carrying amount        
Disclosure of credit risk exposure [line items]        
Financial assets 0 0    
Credit-impaired | Impairment loss allowance        
Disclosure of credit risk exposure [line items]        
Financial assets ¥ 0 ¥ 0    
[1] The comparative information is restated due to change in accounting policy. See Note 2 (5) “Changes in