LONDON -- Here are five small companies that have the potential to double in value, in my opinion.

The problem with such very small caps is that they're inherently riskier, so if you're thinking about investing, you should exercise due caution.

In a couple of cases, the valuation placed by the market on these companies is very small indeed. This is, of course, their attraction. But it also helps illustrates the risks of just how low valuations can get.

In each case, I think the downside is fairly well protected as the companies each exhibit a few good value credentials. But anything is possible.

Savile Group
Smallest of this quintet of micros is human resources consultancy Savile Group (LSE: SAVG.L).

I'm hoping this will prove to be a good turnaround play, which will reward the investment I've already made, over the next few years. But it isn't one in which to invest more money than you can afford to lose.

The company looks to have made a shrewd acquisition recently, which seems to strike a note of optimism about its longer-term prospects.

The half-year results to the end of December show Savile moving back into a small operating profit with a net asset value (NAV) of 2 million pounds and net working capital of 1.64 million pounds, which compares favorably with the market cap of 1.72 million pounds at 11.5 pence per share.

The company then spent 85,000 pounds buying Career Management Consultants, which turned over 5.3 million pounds and made a pre-tax profit of 171,000 pounds last year. But trading had since deteriorated and Savile got it on the cheap.

It's a comfort that two of the directors own over 25% of the shares. Overall, it looks a pretty good investment to me on a risk-reward basis if you're optimistic Savile can return to its levels of profitability from just a couple of years ago.

Autoclenz
Next smallest is car cleaner and minor-repair specialist Autoclenz (LSE: ACZ.L). The shares look tempting to me after I reviewed the portfolio of shrewd investor "DesWalker2" last week.

The market cap is less than 3 million pounds at a share price of 28.5 pence. But in the last full year, Autoclenz made an underlying operating profit of 1.27 million pounds, on sales of 26.6 million pounds, and paid a 1 penny final dividend. This is no asset play but could be a good cash generator in the years to come. And according to the featured investor, there are no plans to de-list -- which would otherwise be a big concern.

Titon
Titon Holdings (LSE: TON.L), which makes ventilators for windows, is something of a perma-value share. But we know that value investing tales patience. At 36.5 pence, Titon weighs in with a market cap of just 3.85 million pounds. This looks like a good value against its net tangible asset value (NTAV) of over 9 million pounds and net working capital of 5.8 million pounds.

The problem, of course, is profitability during lean times when people aren't too worried about new windows. Titon's Korean joint venture also moved back into the red last year. But at some point, the company will surely begin to prosper again, and, until it does so, its balance sheet looks far too healthy for its current valuation.

Despite its small size, Titon retains a full listing.

Datong
Datong (LSE: DTE.L) is another company that looks interesting on a sum-of-the-parts basis. The Leeds-based firm provides covert intelligence-gathering solutions for the likes of police forces and the military. Its products enable authorities to intercept SMS messages and mobile phone calls by secretly fooling mobile phones within a 10-square-kilometer range into operating on a false network.

I don't pretend to understand the technology and Datong's markets. Nevertheless, I bought a few shares on the back of the balance sheet strength and note of optimism sounded in the recent half-year results.

Net working capital of 5.7 million pounds, including 2 million pounds in cash, compares favorably with the market cap of 3.94 million at 28.5 pence per share. Datong made a small first-half operating loss. But the company anticipates a better second half, expecting "certain large orders," and has an order book of 2.36 million pounds. Datong also won a patent infringement claim that had been hanging over it.

Electronic Data Processing
The biggest of the bunch, Electronic Data Processing (LSE: EDP.L) is probably the least likely to double from here but still looks very good value at 42.5 pence. This places the shares on a price-to-earnings ratio of less than 10, while net tangible assets of almost 55 pence per share and net working capital of 25 pence per share mean the merchant distribution software specialist isn't going to the wall any time soon. Furthermore, contracted recurring revenues for annual software licenses and hosting fees represent 76% of sales.

The chairman owns over a fifth of this fully listed company and won't want to sell out too cheaply.

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