diff --git a/NEWS b/NEWS
index 1934c1a..10c2cd4 100644
--- a/NEWS
+++ b/NEWS
@@ -8,8 +8,10 @@ Unreleased, experimental changes
 
     Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
     Its clocks diverge from America/Santiago starting 2017-05-13 at
-    23:00, hiving off a new zone America/Punta_Arenas.  (Thanks to
-    Juan Correa.)  This also affects Antarctica/Palmer.
+    23:00, hiving off a new zone America/Punta_Arenas.  Although the
+    Chilean government says this change expires in May 2019, for now
+    assume it's permanent.  (Thanks to Juan Correa and Deborah
+    Goldsmith.)  This also affects Antarctica/Palmer.
 
   Changes to past time stamps
 
diff --git a/southamerica b/southamerica
index af969ff..6038c3b 100644
--- a/southamerica
+++ b/southamerica
@@ -1210,6 +1210,14 @@ Zone America/Rio_Branco	-4:31:12 -	LMT	1914
 # From Juan Correa (2016-12-04):
 # Magallanes region ... will keep DST (UTC -3) all year round....
 # http://www.soychile.cl/Santiago/Sociedad/2016/12/04/433428/Bachelet-firmo-el-decreto-para-establecer-un-horario-unico-para-la-Region-de-Magallanes.aspx
+#
+# From Deborah Goldsmith (2017-01-19):
+# http://www.diariooficial.interior.gob.cl/publicaciones/2017/01/17/41660/01/1169626.pdf
+# From Paul Eggert (2017-01-19):
+# The above says the Magallanes change expires 2019-05-11 at 24:00,
+# so in theory, they will revert to -04/-03 after that, which means
+# they will switch from -03 to -04 one hour after Santiago does that day.
+# For now, assume that they will not revert.
 
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Chile	1927	1931	-	Sep	 1	0:00	1:00	S