Revolution Bars warned on profits on Monday, despite brisk Christmas party trade.
The cocktail specialist, which has 79 bars in the UK, said it expects full-year earnings to be £12 million, rather than the £16 million analysts had forecast.
Shares in the firm plunged 22p, or 18%, to 99.8p.
Last month pre-booked party revenue at sites open for at least a year was up 11.7%, and total comparable sales up 2.6%.
Boss Rob Pitcher cheered that growth, but said November wasn’t so busy and “Christmas trading came late”.
Total sales in the first-half to December 29 increased 6.4%, but comparable sales dropped 4%.
The company also had to grapple with higher business rates and wage bills.
Pitcher said: "The uplift in like-for-like sales performance over the festive period gives us momentum going into the second half and I'm pleased with the progress being made in refreshing the Revolution brand proposition. However, given the uncertain economic and political outlook we are adopting a more cautious outlook on trading in the coming months."
