Jackson held 2.3% of her £60 million fund in shares of Patisserie Holdings (CAKEP), which were suspended last month as the company warned of 'signficant, and potentially fraudulent, accounting irregularities'.
Chair Luke Johnson has since been forced to issue emergency loans while investors have taken part in a deeply discounted £15 million share placing.
Jackson said she had participated in the rescue rights issue, priced at 50p per share, well below the 430p the shares had been trading at prior to suspension, 'in a small way'.
Fund group Invesco also appears to have emerged as a major backer of the rights issue, upping its stake in the company to 7.8% of the shares last week.
Schroders, Miton and Hargreave Hale were also set to take part in the rescue, according to reports.
Vow to 'learn from this shambles'
'We were very shocked by the news that the chief financial officer had been materially misstating the business's financial position,' said Jackson, in an update to investors.
'As we understand it, there is a viable business despite the fraud and we are reassured that initial restated estimates of profit have not changed in recent weeks.
'Our goal now is to maximise whatever value there is for unitholders, and to ensure we learn from this shambles. Corporate governance is high on our list.'
Despite the hit to the fund over the last month, Jackson has already banked her initial investment in the company, having halved her position after the shares doubled following their flotation in 2014. 'A small crumb of comfort,' she said.