Most fund managers are anonymous characters who between them control assets worth hundreds of billions of pounds. They also take decisions capable of changing the fortunes of both client investors and those of the organisations in which they invest.

We occasionally hear of star performing manager such as Neil Woodford, but most remain well below the radar, quietly going about their business without any fuss, generating steady, solid returns for client investors.

A few years ago, Bestinvest, a wealth adviser, began assembling a list of under-performing investment funds which they eventually developed into an annual report called Spot the Dog.

Over time, Bestinvest has fine-tuned the criterion for inclusion in its Dog Report, tacitly acknowledging that any investor, however well paid, can experience periods of under-performance. Certain types of fund, such as multi-manager and offshore funds, are excluded, but most unit trusts and open-ended investment companies (OEICs) that invest primarily in shares, are included.

The company also measures each fund against an appropriate benchmark, such as the FTSE All-Share Index, to ensure they're comparing like-with-like, but even with these reasonable-sounding filters in place, the definition of what constitutes a dog fund makes for interesting reading.

Anyone can invest in something which goes awry, but the dog funds have reported consistently poor returns for investors. To qualify onto the Bestinvest list, funds must have under-performed against their selected benchmark in each of the three preceding years. And not just by a smidgeon either, but by a cumulative 10% or more over the course of three years.

One assumes the report is a source of embarrassment for fund managers who consistently find themselves 'named and shamed', but perhaps more pertinent for investors is the amount of assets these poorly-performing fund managers hold on investors' behalf.

Although the number of funds appearing on the list has fallen this year, the 64 dogs that do make it account for more than £12 billion in investors' assets. Moreover, there are a further 89 under-performing unit-linked pension funds in which a further £10.9 billion of assets are held. In other words, consistently under-performing fund managers currently control around £23 billion of assets invested by millions of small investors.

Some managers have, thankfully, taken action to rectify matters. Investec, for example, had actually outsourced the management of its Investec American fund to a US-based manager for around a decade, but following a four year run of poor performances, last August the company took the decision to bring the fund management in-house. By the beginning of last month, the fund had disposed of 43 of the 45 shares held before August 2012 and hopes to see a turnaround in fortunes over the course of the next two years.

Well done Investec, but there are other laggards who have taken no such remedial action.

This would suggest that, as is the case with most things in life, if you want something doing properly, then do it yourself. Investors who own poorly-performing unit trusts and OEICs could start by seeing whether their funds are on the Dog List and if there are no moves afoot to rectify matters, they should consider whether they're prepared to put up with continued under-performance.