The price of the investment trust does not always fully reflect the price of the underlying assets. Trusts trade on the stock exchange and operate like a normal share, which mean the price is influenced by supply and demand.
In practice this means that the trust may hold £1000 of HSBC shares and £1000 of Vodafone shares, but it won’t necessarily trade at £2000. It may be that the trust’s price is just £1,900. This ‘discount’ to ‘net asset value’ means investors can pick up £2000-worth of assets for the bargain price of £1900. But it does occasionally work in reverse with a fund trading at a premium.
P.S. In reality, trusts will have more than two companies in them – we were just keeping this example simple!