Royal Mail staff in Croydon have been given £4.5m worth of free shares in the newly privatised company.
The shares have been awarded to 1,200 employees based in and around the borough following Royal Mail's float on the London Stock Exchange last Friday.
But the offer failed to quell anger amongst members of the Communication Workers' Union (CWU), who last week voted in favour of strike action amid concerns privatisation will affect working conditions.
Shares in Royal Mail opened on Friday to huge interest, with some dealing systems buckling under the weight of demand.
In total, Royal Mail awarded £489m worth of free shares to approximately 150,000 employees across the UK.
Speaking after postal workers voted four to one in favour of striking on November 4, Dave Ward, CWU deputy general secretary, said: "Postal workers have spoken very clearly that they care about their jobs, terms and conditions far more than they care about shares.
"The stakes have become much higher for postal workers since privatisation making this ballot more important than ever.
"Postal workers will not be the people who pay for the profits of private operators and faceless shareholders."
Under the privatisation, each full-time worker is entitled to 725 shares worth an initial £3,545.
Their value has already grown by 50 per cent since trading began, leading to accusations that the company had been valued too cheaply.
But Business Secretary Vince Cable denied the taxpayer had been short-changed, dismissing the early surge as "froth".
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