The Devon-based founder of Wetherspoons said trade was "very quiet" over the weekend, days before the Government re-introduced strict regulations on social gatherings.
Tim Martin, founder and chairman of the chain, dismissed claims people would flock to the pub in large groups ahead of the new "rule of six".
From Monday 14 September it is illegal for people to gather in groups of more than six people in England - in any indoor or outdoor setting.
Rule-breakers could face fines of up to £3,200.
Mr Martin, who lives in Exeter, revealed sales were 22.5% down on the 12 September compared to the equivalent Saturday in 2019.
Trade was very quiet over the weekend, as the public weighed up the evidence about the alleged dangers of going out.
Several trade groups, including the British Beer & Pub Association, said the new rule will halt the recovery of hospitality firms who were so badly affected during lockdown.
Mr Martin told investors the safety of pubs has been "widely misunderstood".
The number of people who have visited Wetherspoons pubs since reopening in July.
According to the company, there have been 66 positive coronavirus tests amongst the business' 41,564 employees since reopening in July.
Around £15 million was also spent on installing the necessary hygiene and safety measures to help curb the spread of coronavirus in its establishments.
Mr Martin also revealed a drop in sales throughout July and August meant he would most likely post a loss for the business year to 26 July.