you can check the websites of the companies to see if there is information on how a US shareholder should handle the cash received in lieu of SK Square (S) stock or call them
I am providing a link to IRS form 8937 which the company filed with the IRS regarding the stock split, spinoff, and reverse stock split after the spin-off. you'll note in item 14 that the spin-off was intended to be a taxable distribution. evidently, SK Telecom (T) decided not to issue S as a US stock. that's why you got the cash. there is nothing mentioned in the tax form about allocating basis to S. That's why Schwab shows nothing. Normally when a distribution is taxable no basis is allocated and the holding period starts with the issuance so short-term seems proper. Check all your Schwab 1099-div to make sure the distribution isn't reported there and what's on the 1099-B is cash for the fractional share if S stock had been issued.
https://www.sktelecom.com/img/eng/presen/20211213/IRSForm8937ReportofOrganizationalActionsAffectingB...
Can I instead input the cost basis myself as the amount I received? I believe this would be totally wrong since it was intended for this to be a taxable distribution. however, others may have different opinions.
