The love affair between China's small companies and Aim is coming to an end.

RCG and Asian Citrus have already taken secondary listings on the Hong Kong Stock Exchange in the search for better liquidity. This month West China Cement and China Real Estate Opportunities announced plans to list in Hong Kong and Singapore respectively.

It is easy to understand why. a year ago shares in RCG, a developer of fingerprint and facial recognition systems, more than doubled after it took an additional quote on the Hong Kong Stock Exchange. By December the volume of its shares trading in Hong Kong was more than eight times higher than on Aim.

When Asian Citrus, the Chinese orange plantation group, took a secondary quote in Hong Kong in November, it was only a couple of weeks before 12m shares a day were trading, compared with 500,000 a day on Aim.

However, instead of taking a secondary listing, both CREO and West China Cement intend to quit Aim. Both are consulting their investors and hope to take the majority of their shareholders with them.

Valuation matters as much as liquidity. CREO owns Chinese office, retail and residential property. It has been trading at a 68 per cent discount to its net asset value per share.

Richard David, CREO director, said similar property companies were rated in Asia at a low discount or slight premium. The move to Singapore would potentially re-rate the shares in line with its peers.

West China Cement has been trading on a prospective earnings multiple of about 5. The eight Chinese cement companies quoted on the Hong Kong exchange trade on multiples of between 10 and 15.

It is worth looking at the story of West China in more detail, because it can be argued that its growth story merits an even higher multiple. The company arrived on Aim in December 2006, raising £22m at 105p a share. The funds were to expand cement production from 1.5m tonnes a year to between 8m and 10m tonnes this year – a target the company now hopes to exceed.

Last week it reported operating profits had more than doubled to Rmb616m (£59m) in 2009. The results presentation shows the company's base in Xian – which can be compared with Chicago's position as a gateway to the western US – is ideally placed to benefit from growth in western China, now above the national average.

Part of the reason for a lack of investor interest in the company until the last week or so is the fact that Jimin Zhang, chief executive, holds a 53 per cent stake. Nevertheless Mr Zhang and Poling Low, finance director, have taken pains to keep UK investors informed of the progress of the company, visiting more than twice a year.

Now interest is starting to increase, but it is too late. Ms Low explains that the company does not want to bear the cost of two listings, two sets of advisers, and so forth, or waste management time that could be devoted to further growth.

Aim has enabled West China to grow big enough, even at the current valuation, to move to Hong Kong. News this week that the valuation of trading on stock exchanges in the Asia-Pacific region has overtaken that of European rivals will only strengthen the board's resolve.

Optimists may believe that its story will encourage other Chinese companies to use Aim as a jumping-off point to bigger things. But my feeling is that the moment has passed. One of the last Chinese companies to join Aim was China Eastsea Business Software, back in 2008. On March 24 its shareholders will meet to vote on cancelling the quote.

Ironically these companies will be quitting just as UK investors appear on the verge of kindling a passion for Chinese investments. If they deliver on their promises, the remaining Chinese companies on Aim should see their valuations improve, if only on the grounds of scarcity.

Theory of relativity

London Stock Exchange statistics show that another 15 companies left Aim in February, taking the total this year to 34, only six fewer than in the first two months of last year. Before any more of the 1,268 companies on the market consider quitting, executives might like to take a look at the exchange's first practical guide to investor relations, to be published next week.

For some bigger companies, it looks like an exercise in teaching grandmother to suck eggs. But many of the boards of smaller companies, who are the most likely to complain of poor valuations and lack of liquidity, could do worse than read, mark, learn and digest how things should be done to keep investors happy.