** Professional services company's shares  MMC.N  rise ~2%
to $116.85 premarket
    ** Stock set for a second straight session of gains
    ** Warren Buffett's Berkshire Hathaway  BRKa.N  discloses a
new $499 million stake in co
    ** Berkshire also reveals a $4.1 bln stake in oil major
Chevron  CVX.N  and an $8.6 bln stake in wireless carrier
Verizon  VZ.N   urn:newsml:reuters.com:*:nL1N2KM2HX
    ** VZ shares rise 4% premarket, while CVX up 3.4%
    ** MMC stock rose ~3% in 2020

 (Reporting by Akanksha Rana in Bengaluru)