Citywire AAA-rated fund manager Mark Hawtin talks about his concerns over the proposed IPO of Twitter, which is expected to float next month.

Hawtin, who runs the GAM Star Technology fund, says Twitter's float is likely to compare unfavourably with that of Facebook, which has a much higher user base and greater profitability. 

He voices his concerns over Twitter's ability to stomach capital losses and what its costs are. However, Hawtin has not ruled out investing in it.