Schiehallion (MNTN ), the £880m Baillie Gifford pre-flotation ‘unicorn’ fund, has launched a $20m (£16.4m) share buyback programme in response to the huge 57% discount that has opened since its C-shares converted into ordinary shares six weeks ago.

The investment company’s board said it and investment manager Peter Singlehurst were ‘focussed on maximising returns for shareholders over-the long term’ and so their ‘priority’ is to have enough capital to ‘deliver on its objectives, including supporting existing investments and satisfying the company’s ongoing working capital requirements’.

However, they believe the current deep discount offers ‘an attractive investment opportunity’ with the level of buybacks dictated by the ‘limited available capital’.

The US-focused closed-end fund had $162m worth of cash and treasury bills at the end of July, according to its half-year report. The board said it would keep its capital allocation and buyback policy under review.

Like many of its growth capital and private equity peers, Schiehallion has seen its previously highly-rated shares suffer a drastic derating.

From trading at premium in autumn last year, the shares sank to a 20% discount by the end of 2022, a deficit that widened to 39% by September before expanding again after the conversion of the C-shares.

The conversion took place after 85% of the $700m raised in the C-share issue two years ago was invested.

The shares had more than halved this year to 45 cents, reducing their market value to £379m. This morning they slipped another 5% to 42 cents.

Peel Hunt analyst Markuz Jaffe said while the buyback programme was ‘not the largest’ the company’s shares are ‘starting from one of the widest [discounts] across the universe we track’ and any activity might provide ‘welcome relief to such a depressed share price’.

Schiehallion’s decision to purchase its own shares comes as private equity investment companies are increasingly undertaking activity. Pantheon International (PIN ) is undertaking a £200m buyback programme, while Chrysalis (CHRY ) is considering a £100m scheme and Abrdn Private Equity Opportunities (AEPO ) is also eyeing a return of capital in this way.