underwriteun·der·write /ˌʌndəˈraɪt/ verb (past tensepst underwrote /-ˈrəʊt-ˈroʊt/, past participlepp underwritten /-ˈrɪtn/) [transitiveT]1FINANCE if a financial institution underwrites a SHARE ISSUE, it arranges to sell shares to investors and agrees to buy any shares that are not bought by themAn underwritten offer may be the only way a company can raise money.
2INSURANCE if an insurance company underwrites an insurance contract, it agrees to pay for any loss covered by the contract 3FINANCEto agree to pay the cost of something and to take financial responsibility for it if it failsA local company has underwritten some of the development costs.
The government has agreed to underwrite the project with a grant of £5 million.