RBS's Citizens Financial makes a tepid market debut
The offering, which raised $3.01 billion for RBS, is the second biggest in the United States this year after Alibaba Group Holding Ltd's $25 billion IPO last week.
Citizens Financial's IPO was priced at $21.50, below the expected range of $23-$25.
RBS owned 100 percent of Citizens Financial before the offering.
Citizens Financial's shares were at $21.64 shortly after start of trading.
(Reporting by Tanya Agrawal; Editing by Joyjeet Das)