The worst performing UK equity fund of 2018 was the Quilter Investors UK Equity Income fund, managed by Neil Woodford.
The £131m fund, which is available only to clients of Quilter, lost 26.5 per cent in the period, much worse than the performance of Mr Woodford's flagship Woodford Equity Income fund, which lost 12 per cent.
Woodford Investment Management declined to comment.
The data, provided by AJ Bell and pulled from FE Analytics, covered the period from January 1 2018 to December 7 2018.
It found the absolute worst performing fund, across all asset classes, was the £211m Jupiter India Select, which lost 28.8 per cent, while the £848m Jupiter India fund, the third worst performer, has lost 25 per cent.
It was a tough year for emerging market equities generally, with the MSCI Emerging Markets Index losing 12 per cent, and seven of the twelve worst performers in the funds universe representing emerging market mandates.
If emerging markets have performed poorly, US equities have generally been strong performers.
That was reflected in an analysis of the best performing funds, with the £1.9bn Baillie Gifford American fund the best performer, having returned 26 per cent. The fund has significant exposure to technology stocks and has lost 12 per cent over the past three months.
The next best performing fund was the £1.7bn Polar Capital Healthcare Opportunities, which returned 21.7 per cent.
The best performing investment trust was the £239m Lindsell Train IT, which returned 44.7 per cent.
The performance of this trust was driven by the fact the management was reluctant to issue new shares, and its largest investment, Lindsell Train Ltd, is the management company that runs the trust and other funds.
This private company is owned by Mike Lindsell, Nick Train and another individual, as well as the investment trust.
The private shareholders' reluctance to sell any of their shares in the private company to the shareholders of the investment trust means new shares in the investment trust are not issued, and nor is the trust heavily marketed.
The board of the trust says a mathematical formula is used to calculate the value of its shareholding in the investment management company.
Laura Suter, personal investment analyst at AJ Bell said: "This is a case where you need to look under the bonnet to see where the performance has come from.
"Renowned investor Nick Train has undoubtedly had a good year, with his Lindsell Train Global Equity fund also making the top performers this year, returning 15 per cent.
"However, the Lindsell Train Investment Trust is now trading at a 45 per cent premium to the net asset value, having started the year at around a 13 per cent premium. The trust returned 44.8 per cent in share price terms this year, while the net asset value has risen by a more modest 10 per cent.
"The trust’s biggest holding by far, at 47 per cent, is the fund management company running it – Lindsell Train, an unlisted company, and the reason for the premium is that investors feel the management company is undervalued by the trust’s board.
"The board clearly disagrees, and anyone buying in at this price needs to seriously consider whether they want to pay almost half as much again for the value of the assets."
Meanwhile, the continued travails of the UK property sector impacted on the performance of Real Estate Investment Trusts (REITs), which were among the very worst investment trust performers.
INTU Properties, New River Retail, and Capital and Regional were three of the four worst performers.
The absolute worst performer was the £196m Catco Reinsurance, which invests in insurance bonds, and lost 79 per cent.
The best performing investment trust sector in 2018 was biotechnology and healthcare, which returned 16 per cent, according to separate data from the Association of Investment Companies.
This article has been amended post publication to reflect that the Jupiter India Select fund has made a loss of 28.8 per cent in the year to date, not 278.8 per cent as mistakenly stated.