** Real estate co's shares JOE.N jump as much as 11.2% to
$19.82, hitting a 20-month high
** Last up ~10%, stock among top pct gainers across U.S.
exchanges; set for its biggest one-day pct gain in over 6 years
** JOE to replace property and casualty insurance co RLI
Corp RLI.N in the S&P 600 SmallCap index .SPCY before
markets open on Dec. 5 urn:newsml:reuters.com:*:nPn8wGBnVa
** RLI to replace insurance holding co W.R. Berkley Corp
WRB.N in the S&P 400 MidCap .MID , while WRB to replace
Viacom Inc VIAB.O in the S&P 500 .SPX
** CBS Corp CBS.N , Viacom to close their all-stock merger
on Dec. 4, cos said on Nov. 25 urn:newsml:reuters.com:*:nL4N2853C1
** RLI down ~5%, WRB down ~1% in morning trade
** JOE up ~49% so far this year
(Reporting by C Nivedita in Bengaluru)
((C.Nivedita@thomsonreuters.com))