International Public Partnerships (INPP), the £2.3bn infrastructure fund that surprised investors with a £250m investment in Sizewell C nuclear power plant project last month, has sold down part of its 10% stake in Angel Trains.

The investment company has agreed to sell 1.6% of the rolling stock leasing company to London-based Arjun Infrastructure Partners for £32m at an “attractive premium”.

Analysts at its corporate broker Deutsche Numis estimated the transaction was priced at 28.5% above the previous valuation at 31 December. They said this could add 2.5p to net asset value (NAV) per share which stood at 144.7p at the end of last year, but which they believe has grown to 146.59p.

The market liked the validation of Amber’s valuation and shares in the 7%-yielder rose 1.5% to 125.2p.

With the stock trading at a 16% discount to NAV, INPP will use the money to support its ongoing £200m buyback programme and help fund the plan to invest £50m a year up to 2030 in the construction of the nuclear plant in Suffolk.

INPP will own 8.4% of Angel Trains after the sale, which is expected to close in the next few weeks, and will retain a seat on the board through fund manager Amber Infrastructure.

Including today’s part disposal and the £49m made from last month’s sale of loans to the UK’s school buildings programme, INPP has realised over £345m of proceeds since July 2023, equivalent to 13% of the portfolio of energy transmission, social, transport and digital infrastructure assets.

INPP chair Mike Gerrard said: “The company remains focused on optimising its portfolio while supporting both capital returns and attractive reinvestment opportunities.”