FTSE 250 investment trust RIT Capital Partners said that net asset value (NAV) per share hit an all-time high by the end of the first half. However, the company gave a cautious outlook on the current state of global stock markets, saying the search for assets with attractive valuations not conditional on short-term monetary policies by central banks "has become increasingly challenging"."We have become uncomfortable in participating in liquidity fuelled markets and are sceptical as to whether the current degree of investor complacency can be maintained," said chairman Lord Jacob Rothschild.Net assets were valued at £2.173bn by 30 June, up £27m from £2.146bn at the end of 2013. NAV per share increased to 1,401p, up 17p from 1,384p six months earlier.This represents a total return, including a 14.7p interim dividend, of 2.4% for the first half, helped by a decent performance from its long exposure to equities and private investments in funds, partly offset by a negative impact from currency movements.During the same period, the share price total return including the dividend was 5.6%.The company reported a net profit of £51.8m for the first half, down sharply from the £253m made in the first six months of 2013, with the prior year benefitting from higher gains on portfolio investments held at fair value.BC