Investment trusts' share prices have widened to an average 14% discount to the value of net assets towards the end of the first half of 2023.
This compares to an average of 12.3% at the end of last year, according to an analysis by the Association of Investment Companies of data from Morningstar.
Based on month-end data, is the biggest discount since February 2009 for investment trusts focused on equities, the AIC said.
In the first half of the year, the average investment company generated a return of 0.3%, though that number obscures a wide scattering between sectors.
Investment companies in the private equity and technology sectors returned well over 25% while Chinese equities, infrastructure and commodities were down at the bottom with double-digit losses.
Core equity sectors are somewhere in between, with Europe and Japan doing better than the UK and Global.
Discounts have also seen a wide dispersal of numbers and some notable shifts since the start of the year.
Property sectors are still showing among the biggest discounts, with UK Residential and European Property above 40%.
But they are eclipsed by the growth capital sector, at just under a 50% discount on average, even though the wider private equity sector has seen average discounts narrow to less than 4% from above 25% six months earlier (mostly thanks to the swing at 3i Group PLC (LSE:III) from a discount to a premium).
In equities, the North America sector continues to show the biggest discount, at 26%, followed by Global Smaller Companies at almost 16%.
"Discounts have gone a little wild," said Nick Britton, the AIC's head of intermediary communications.
"Are things really that bad today?" he pondered. "Or is Mr Market offering us one of those rare opportunities to stock up on some core equity holdings at a bargain-basement price?"
Analysts at Stifel noted in April that average discounts have topped 16% occasionally in the past year, which they said highlighted a wealth of cheap-looking funds that could eventually prove bargains for contrarian investors.