An unprofitable business technology start-up with a funny name turned in the best stock debut this year on yesterday, underlining how investors' appetite in the latest tech boom now extends beyond hot web companies like Facebook.

Splunk - which helps businesses organise and make sense of all the information they collect, a trend known as "Big Data" - soared 109% on the Nasdaq Stock Market, sending its market value above $3bn. It was especially impressive given the broader stock market was down.