A former London banker, his wife and a friend have been sentenced in a $NZ4.5m insider trading scheme uncovered by the UK's Financial Services Authority.

Tower, the insurer controlled by Guinness Peat Group, may return capital to shareholders, chairman Tony Gibbs told the annual meeting.

Equities on Wall St were up overnight, lifted by better-than-expected earnings from Exxon Mobil and a pick-up in US consumer spending that surpassed forecasts.

Growth from India, Vietnam and Saudi Arabia supporting traditional sources.

Technical advances help windsurfing company chase overseas sales.