** Shares of internet services firm VeriSign VRSN.O rise 2.3% premarket, on track for seventh straight increase if gains hold
** Shares closed at $203.95 on Friday, highest since January
** Warren Buffett's Berkshire Hathaway BRKa.N increases stake in co to 13,193,349 shares as per SEC filing on December 26
** Berkshire purchased over 143,000 shares between Dec. 20 - Dec. 24, and 234,312 shares between Dec. 17 - Dec. 19 as per Dec. 19 filing
** Stake worth about $2.7 billion at VRSN's last closing price
** Berkshire is co's largest stakeholder as per LSEG data
** Co on track for nearly 9% monthly rise, its best month since October 2022
** 2 of 4 brokerages rate the stock "strong buy", 2 "hold"; median PT is $210
** Up to Friday's close, stock lags S&P 500 .SPX, down nearly 1% year-to-date
(Reporting by Lisa Mattackal)