BUZZ-Serco: announces sale of BPO unit to Blackstone
** Outsourcer Serco opens up c.3 pct & among top FTSE midcap gainers
** Co announced sale of its Business Process Outsourcing operation to PE firm Blackstone (NYSE: BX - news) for 250 mln stg & says will use proceeds to reduce indebtedness
** Although sale flagged earlier on, analysts laud finalisation as another step towards recovery for co marred by string of contract problems and a scandal last yr
** Nearly a fifth of a full-day's volume traded through in less than first five mins of trade
** Up to Tuesday's close, stock had fallen 21 pct YTD vs c.5 pct fall in broader midcap index
(RM (LSE: RM.L - news) : esha.vaish.thomsonreuters.com@reuters.net)