{'fraction_non_alphanumeric': 0.014018691588785047, 'fraction_numerical': 0.01588785046728972, 'mean_word_length': 4.820652173913044, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Insider Trading Before IPO Lockup Expiry Dates: The UK Evidence

We analyse the trading behaviour of insiders before the termination of IPO lockup arrangements of a sample of 831 IPOs on the London Stock Exchange over the period 1999 to 2007. We find that the average lockup period of 365 days is significantly higher than the 180 days in the US, and large insider trading activity occurs during this period as insiders sell in over-performing and buy in underperforming IPOs. The results suggest that this early trading activity is likely to be pre-arranged with the underwriters, and that, while the sell trades can be considered as an early release following good performance, the buy trades are likely to be undertaken to support the price of underperforming IPOs. These IPOs are also more likely to have longer lockup periods, larger proportion of shares locked up, and more likely to be backed by venture capitalists. The documented negative price reaction on lockup expiry dates is positively related to the probability of early buys of insiders, not early sells.