(Adds deal details, context, Eversource Energy statement)
By Karan Nagarkatti and David French
Aug 13 (Reuters) - California Water Service Group said on Monday it raised an all-cash offer to buy SJW Group by nearly 3 percent, the latest attempt to woo its fellow California utility out of a proposed tie-up with Connecticut Water Service Inc.
The trio form part of a four-way merger battle begun in March when SJW announced a planned combination with Connecticut Water, a move that drew local suitors for both businesses who argued regional consolidation was better than a trans-America deal.
CalWater's new offer for SJW of $70 per share, detailed in a market filing, represents a premium of 12 percent to the stock's Monday close and values the company at about $1.45 billion.
That is above the $68.25 bid CalWater made in April, which was rejected by SJW citing regulatory and financing concerns.
The new proposal also sweetens terms for SJW by offering it up to two board seats and opening the possibility that SJW management would gain a role in the combined company.
CalWater also offered to consider alternative transaction structures - details of which were not disclosed in the statement - as well as an additional $0.50 per share for every quarter the deal was delayed by regulatory approval beyond a set timetable.
SJW shares were up 7.3 percent at $66.95 in after-hours trading, while California Water was up 7 percent at $42.90.
Responding to CalWater's offer in a separate filing, SJW said it would "carefully review and consider all aspects of CalWater's revised proposal."
CalWater's offer comes a week after SJW said it had agreed to a revised deal with Connecticut Water, in which it would buy the New England utility for $1.1 billion in cash.
Connecticut Water has separately attracted interest from Eversource Energy, which on Monday said in a statement it remained committed to its $64 per share offer made in July and rejected by Connecticut Water.
Water utilities, particularly in California which has experienced severe drought conditions in recent years, often see mergers and acquisitions as a way to increase scale and efficiency. (Reporting by Karan Nagarkatti in Bengaluru and David French in New York; editing by Maju Samuel and Tom Brown)