Food groups are also having a good December, with some supermarkets claiming double-figure percentage growth over the past month. But retail experts are warning investors not to get too carried away. Analyst Verdict estimates pre-Christmas sales up by 6%, but chairman Richard Hyman cautioned: 'It's easy to think that because the volume of sales are up, profits will be up by the same amount. Sadly that doesn't follow. There is still a huge amount of price pressure and virtually no retail inflation, so margins are very low.'