guarantor; acceptor; underwriter
A person who assumes responsibility for an obligation, such as a loan guarantor, the acceptor of a promissory note, or an underwriter of a stock issue. The specific meaning depends on the financial or legal context.
See also: 引き受け (ひきうけ)
As the guarantor of the loan, he guaranteed his son's debt.
The acceptor of a promissory note is the person who undertakes to pay it.
The underwriter of a new stock issue is often a securities company.