Ordinary investors will be awarded 'bonus' shares in NatWest Group if they hold onto stock they acquire in the taxpayer-backed bank, under a plan expected to be finalised by ministers later this month.

Sky News has learnt key details of the options being explored by the Treasury for a multibillion pound retail offer of NatWest shares, including a likely £10,000 cap on applications from members of the public. Jeremy Hunt, the chancellor, announced in last year's autumn statement that he would explore a mass-market share sale "to create a new generation of retail investors".

Since that point, further buybacks by the bank and stock sales by the government have reduced the taxpayer's stake to around 28% - worth about £7bn at NatWest's current valuation. The retail offer will be launched alongside an institutional placing of shares in the bank which could in aggregate lead to the Treasury's stake falling to as low as 10%, sources indicated this weekend.

If investor demand turns out to be greater than expected, the reduction could be even more substantial, they said. That would put the government within striking distance of returning NatWest to full private ownership 16 years after the lender was rescued from the brink of collapse with £45.5bn of public money.

This weekend, sources said that options under active consideration by Treasury officials included a minimum investment of £250, to encourage a wide participation in the retail offer. A ceiling of £10,000 was "likely.