** Defense and space systems maker Karman Holdings' KRMN.N shares fall 6.1% to $52.80 premarket
** KRMN late Monday launched secondary offering of 20 million shares being offered by some existing stockholders
** Selling shareholders include private equity firm Trive Capital and Karman CEO Tony Koblinski
** Citigroup and Evercore ISI are book-running managers for proposed offering
** KRMN went public in February after 23 million share IPO priced at $22 apiece
** All five brokerages covering stock rate "buy" or higher; median PT $50.50 - data compiled by LSEG
** As of last close, KRMN stock has more than doubled since debut on February 13
(Reporting by Arasu Kannagi Basil in Bengaluru)
((ArasuKannagi.Basil@thomsonreuters.com;))