Underwrite

v. give one's signature and thus receive liability; financially sponsor, support through donations; guarantee the sale of shares (Finance); provide insurance; write underneath or at the end of (a document)

Underwriting refers to the process that a large financial service provider (bank, insurer, investment house) uses to assess the process of providing access to their product like providing equity capital, insurance or credit to a customer. The name derives from the Lloyd's of London insurance market in London, United Kingdom. Financial bankers, who would accept some of the risk on a given venture (historically a sea voyage with associated risks of shipwreck) in exchange for a premium, would literally write their names under the risk information which was written on a Lloyd's slip created for this purpose.
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Verb
1. guarantee financial support of; "The opera tour was subvented by a bank"
(synonym) subvention, subvent
(hypernym) undertake, guarantee
2. protect by insurance; "The insurance won't cover this"
(synonym) cover, insure
(hypernym) guarantee, warrant
(hyponym) reinsure
(verb-group) cover
(derivation) insurance broker, insurance agent, general agent, underwriter

(v. t.)
To write under something else; to subscribe.
  

(v. t.)
To subscribe one's name to for insurance, especially for marine insurance; to write one's name under, or set one's name to, as a policy of insurance, for the purpose of becoming answerable for loss or damage, on consideration of receiving a certain premium per cent; as, individuals, as well as companies, may underwrite policies of insurance.
  

(v. i.)
To practice the business of insuring; to take a risk of insurance on a vessel or the like.
  

To guarantee, as to guarantee the issuer of securities a specified price by entering into a purchase and sale agreement . To bring securities to market.