SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue recognition (Details) - USD ($)	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
IPO Distribution Services
Revenue from contracts with customers	$ 4,111,076	$ 8,185,595	$ 12,565,574
Currency Exchange Service
Revenue from contracts with customers	$ 5,326,985	$ 6,904,233	$ 12,607,089

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ Details