UPDATE 1-Salesforce to buy MuleSoft in $6.5 bln deal

(Adds details on deal, background, shares)

March 20 (Reuters) - Salesforce.com Inc said on Tuesday it would buy software maker MuleSoft Inc for about $6.5 billion, including debt, just a year after the software company went public.

MuleSoft shareholders would get $36 in cash and 0.0711 of a Salesforce share, or $44.89 per share. The per-share price represents a premium of 36 percent to Mulesoft's Monday close.

MuleSoft shares were up 4.5 percent in extended trading after rising 27 percent during the day. Salesforce shares were down 2 percent after the bell.

Excluding debt, the deal was valued at $5.90 billion, according to Reuters' calculation.

MuleSoft listed on the New York Stock Exchange on March 17 at $17 apiece. It closed up 40 percent on the first day of trading, giving it a market value of nearly $3 billion.

Reuters had reported about the deal earlier on Tuesday.

Salesforce Ventures, the company's venture capital arm, led a $128 million funding round in MuleSoft in 2015.

MuleSoft, which makes software that automatically integrates disparate data, devices and applications to help businesses networks run faster, counts Coca-Cola Co, McDonald's Corp , Salesforce and Spotify among its customers.

BofA Merrill Lynch is Salesforce's financial adviser and Goldman Sachs advised MuleSoft. (Reporting by Supantha Mukherjee in Bengaluru; Editing by Shounak Dasgupta)