Sweett has been hit by delays in selling stakes in the school projects which will raise £4m.
The company said: “As a consequence of delays in completing certain transactions, principally the Inverclyde Schools and Dumfries & Galloway Schools PFI projects asset sales, the announcement of results for the year to 31 March 2012 will be deferred until August.
“The timing of these completions means that the associated profit will not now fall in the 2011/12 year and will cause the results for the year ended 31 March 2012 to be commensurately lower than market expectations.
“However, both of the transactions are due to be completed shortly.
“Given the action taken last year to reduce our overhead costs, the underlying trading performance continues to be encouraging.”
The news sent Sweett’s share price tumbling by 17% in early trading.
The company launched a cost-cutting drive last year which is expected to deliver £2m in annual savings from April.
The firm’s last set of interim results showed it made a pre-tax loss for the six months to September 30 2011 of £193,000 on revenue of £36.1m.
Sweet announced plans to sell its stake in the Inverclyde Schools PFI project for £2.m in January and in April revealed it was selling its Dumfries & Galloway stake for £2m.