underwriternoun [ C ]
uk/ˈʌndəˌraɪtər/us/-dəraɪṱɚ/INSURANCE an organization, or someone working for one, that underwrites insurance policies:
Mortgage insurance underwriters refuse coverage for loans made to borrowers with credit scores less than 575.
STOCK MARKET a financial organization, or someone working for one, that underwrites new shares when they are offered for sale:
The biggest underwriter was Swiss Bank Corporation in London agreeing to back one third of the shares.