Originally Posted by
Land-of-Miles
This may be due to the rigours of a US listing (e.g. SARBOX requirements etc). Many companies are delisting from the US and re-listing, or concentrating their listing on the LON Market. There may be no more sinister purpose than this.
There is anecdotal evidence which suggests that Sarbox is one reason why some companies are de-listing from US exchanges.
However foreign companies would still have to comply with that specific piece of legislation if they have a certain number of US shareholders (eg: through the use of ADRs).
Therefore it may not be the sole reason for a de-listing.