UPDATE 1-Muni bond sales fall 12.9 percent in first half of 2017

(Adds details about refundings and top issuers)

NEW YORK, July 3 (Reuters) - U.S. states, cities, schools and other issuers sold $187.2 billion of debt in the first half of 2017, a 12.9 percent drop from the same period last year, according to Thomson Reuters data released on Monday.

Refundings of outstanding bonds plummeted 26 percent to $99.4 billion year to date, compared with $134.3 billion for the first half of 2016. New money bond issuance was up 8.7 percent.

Bank of America Merrill Lynch was the top underwriter during the period between Jan. 1 through June 30, with $26.7 billion of debt in 282 deals.

California was the top issuer in 2017's first half by selling a total of $4.6 billion of debt, followed by Dormitory Authority of the State of New York with $3.6 billion of debt in 11 deals and California Health Facilities Finance Authority with $3.1 billion of debt in six deals. (Reporting by Laila Kearney; Editing by Dan Grebler and Jonathan Oatis)