Shares in UK Commercial Property (UKCM ) and Tritax Big Box (BBOX ) rose after the real estate investment trusts confirmed the terms of an all-share merger outlined last month.

UKCM, a £1.2bn industrials-weighted generalist UK commercial property fund managed by Abrdn, jumped 4.5%, or 2.9p, to 67.6p as the majority of its board, but unusually excluding chair Peter Pereira Gray, approved the sale of the company to Big Box, a £5.1bn logistics specialist which is also part of the Abrdn group following its acquisition of manager Tritax three years ago.

Big Box shares gained 2.6%, or 3.9p, to 154p after it agreed to issue 0.444 new shares for every UKCM share based on their respective 31 December asset valuations of 177.2p and 78.7p.

Both companies need the support of 75% of voting shareholders. Phoenix Life, a 43% UKCM shareholder, has given an irrevocable undertaking to support the sale and Investec Wealth, a 13% shareholder, has signed a non-binding letter of intent do so.  The merger is expected to take effect in May.

BBOX chair Aubrey Adams claimed the merger was ‘compelling’ on strategic and financial grounds for both sets of shareholders.

‘UKCM has assembled a high-quality logistics-oriented portfolio with a South-East and Midlands focus and significant embedded rental reversion potential, all characteristics which are complementary to BBOX’s current portfolio.

‘The combination grows BBOX’s exposure to “last mile” and urban logistics assets which have the potential to enhance returns of the existing portfolio.’

Margaret Littlejohns, senior independent director of UKCM, said: ‘The UKCM recommending directors believe this transaction allows all UKCM shareholders to benefit from continued investment in a Reit, but with significantly larger scale and improved share liquidity, as well as addressing the factors we believe have contributed to the persistent discount at which UKCM’s shares have traded for many years.’

BBOX shares have fallen from 160p when the talks were announced, but UKCM has risen from 64p to 68p. This is the latest in a string of corporate actions involving investment companies run by the Abrdn group with stable mate Abrdn Property Income (API ) seeking shareholder approval next week for its merger with Custodian Property Income (CREI ).