It’s a great way to save, and profitable too – especially if you work for a company performing well on the stock market.

More than 2.3 million employees in listed companies use Sharesave, putting in £5 to £250 per month over three or five years. Companies discount the option price at which a share can be bought by up to 20 per cent.

It’s proved a money-spinner for many, even in rocky stock markets.

More than 200,000 Asda supermarket workers, for instance, have cashed in on Sharesave since 1999.

Recently, more than 16,000 of them shared a £43 million bonus when their scheme matured after shares of parent company Wal-Mart showed a 50 per cent rise since 2006 – and 95 per cent of them sold all their new shares immediately to get the cash windfall.

Asda staff who put the maximum £250 per month into the scheme got a bonus of more than £4,500 on £9,000 invested. About 25,000 Asda workers joined the next Sharesave scheme from March 2009, and 50,000 of the total 165,000-strong workforce are in such a plan.

In 2008, more than 2,400 bus and rail drivers with transport firm Stagecoach cashed in, receiving about £6,300 for an average gain of more than £3,600 each.

Clearly, Sharesave encourages many workers on low incomes to make regular savings over several years.

The benefits are two-fold: employees are introduced to share ownership at a guaranteed profit, because if the share price falls during the saving period they can take their money, plus bonus, and walk away at the end with a lump sum.

Firms gain, because workers receive an incentive to work efficiently to maximise profits.

Nearly all of us need to save more, which makes it harder to understand the decision of Her Majesty’s Revenue & Customs (HMRC) to cut the rate paid on cash in three-year Save As You Earn (SAYE) schemes from 1.08 per cent to 0.54 per cent.

For early leavers, who fail to complete the specified saving period, the rate is cut from 0.50 per cent to 0.36 per cent.

For savers over five years, the rate falls to 1.42 per cent. These rates apply to new schemes, not those in operation.

Roy Maugham, tax partner at accountants UHY Hacker Young, says that, by setting interest rates close to zero, employees who later decide not to exercise their options will see almost no return on money they have locked away. “HMRC could not have done this at a worse time. The recession has forced many growing companies to freeze pay and recruitment, and some use SAYE schemes to reward staff with the offer of a stake in the company instead.

“HMRC is now throwing cold water on these attempts to incentivise and reward the most promising employees.”

All interest and any bonus paid on the maturity of Sharesave schemes are tax-free, so the taxman might think his revised rate is not far out of line with, say, the 0.80 per cent currently paid as Premium Bond prizes and plenty of sub-one per cent bank and building society account rates.

However, it is probably more important than usual to keep interest rates on SAYE schemes attractive, because the gloom surrounding UK shares will persuade many employees not to become involved, and to waste money which would be taken from their pay packet if they joined Sharesave.