It is almost exactly a year since Standard Life abandoned its mutual status and launched itself on the stock market, turning millions of policyholders into small shareholders.

For those who kept their free shares, the float has proved a great success. For those with the foresight or good fortune to buy additional shares, it has been even more lucrative.

The shares have soared from an issue price of 230p (or 218.5p for policyholders given preferential terms) to about 340p. Add in a 5.4p dividend paid in May and shareholders have enjoyed a total return of up to 58 per cent.

It gets better. Next month shareholders who have continuously held the shares since flotation will receive one extra “loyalty share” for every 20 held. The company expects to fork out additional shares worth £238 million over the next few weeks. About 1.7 million people will benefit from the perk.

The average small shareholder, with 641 shares, today stands to make a total profit – on paper at least – of about £850 since the insurer floated. It is a coup for popular capitalism not seen since the 1990s, the era of big privatisations and building society demutualisations.

You could argue that the company was floated too cheaply, transferring wealth from policyholders who cashed out to outside investors. But the float took place at a skittish time for share markets and there was speculation at one point that the float would have to be abandoned.

Once the July 10 qualification date for loyalty shares has passed, shareholders need to take stock. There is no longer any special incentive to hang on to the shares. And there are other reasons why now may be a good time to sell.

First, all life assurers are a geared play on the stock market. They rise disproportionately when markets go up and fall with a thud when they go down. If you believe that the stock market bull run – now in its fifth year – must fizzle out soon, this may be a timely moment to bow out.

Secondly, for some small shareholders, Standard Life shares may represent a large chunk, if not all, of their equity holdings. There is much to be said for diversifying, however solid a single shareholding appears.

That apart, Standard Life looks like a share with life still in it. It remains at a relatively early stage in its turnaround plan. A cost-cutting campaign has farther to run and the rehabilitation of the company in its two key overseas markets of Canada and Germany has only just begun.

It has a strong brand and there are numerous opportunities to exploit it better. The company’s dominance of the market for Sipps (self-invested personal pensions) shows how the brand can be harnessed successfully, though it has to be said that another brand extension, Standard Life Bank, has been a flop. Meanwhile, the fund management division, Standard Life Investments, posts investment results that put rival houses to shame, which should help it to win more business.

Investors who can afford to lose their money should stay on for more. After July 10 they may also, usefully, put the shares in an Isa wrapper to avoid tax.

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