July 22 (Reuters) - Shares of Couchbase Inc (BASE.O) jumped more than 23% in their Nasdaq debut on Thursday, giving the database software company a market capitalization of nearly $1.2 billion. The shares opened at $29.60, well above $24 at which the company sold roughly 8.34 million shares in it upsized IPO Wednesday. The company, which raised $200 million in its IPO, had earlier planned to sell 7 million shares priced between $20 and $23 each. It is backed by investors such as GPI Capital, North Bridge Venture Partners and Accel. Couchbase"s software helps customers, including media giant Comcast Corp (CMCSA.O) and e-commerce firm eBay Inc (EBAY.O), manage their databases on web and mobile applications through its NoSQL cloud database service. Reuters reported in March that Couchbase had registered for a stock market listing that could value it as much as $3 billion, citing people familiar with the matter. The company"s market debut comes at a time when demand for data storage, security and processing has surged on a global scale with businesses moving to a remote working model due to the COVID-19 pandemic. Morgan Stanley and Goldman Sachs were the lead underwriters for the offering.