Calpine Corp (CPN): Billionaire Andreas Halvorsen’s Viking Global Significantly Increases Its Stake

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Page 18 of 18 – SEC Filing

Schedule 13G PAGE 18 of 18

CUSIP No. 131347304

EXHIBIT A – JOINT FILING AGREEMENT

This joint filing agreement is made and entered into as of
this 5th day of July, 2016, by and among Viking Global Investors LP,
Viking Global Performance LLC, Viking Global Equities LP, Viking Global
Equities II LP, VGE III Portfolio Ltd., Viking Long Fund GP LLC, Viking Long
Fund Master Ltd., O. Andreas Halvorsen, David C. Ott and Daniel S. Sundheim.

The parties hereby agree to jointly prepare and file a Schedule 13G
with respect to Calpine Corporation, as well as any amendments thereto,
pursuant to the Securities Exchange Act of 1934, as amended.

IN WITNESS WHEREOF, the parties hereto have executed this agreement
as of the date first set forth above.

Dated: July 5, 2016

/s/ O. ANDREAS HALVORSEN
By: O. Andreas Halvorsen – individually and
as an Executive Committee Member of
VIKING GLOBAL PERFORMANCE LLC, on behalf
of itself and VIKING GLOBAL EQUITIES LP,
VIKING GLOBAL EQUITIES II LP and VGE III PORTFOLIO LTD.,
and as an Executive Committee Member of
Viking Global Partners LLC, on behalf of
VIKING GLOBAL INVESTORS LP, and as
an Executive Committee Member of
VIKING LONG FUND GP LLC, on behalf of itself
and VIKING LONG FUND MASTER LTD.

/s/ DAVID C. OTT
By: David C. Ott – individually and
as an Executive Committee Member of
VIKING GLOBAL PERFORMANCE LLC, on behalf
of itself and VIKING GLOBAL EQUITIES LP,
VIKING GLOBAL EQUITIES II LP and VGE III PORTFOLIO LTD.,
and as an Executive Committee Member of
Viking Global Partners LLC, on behalf of
VIKING GLOBAL INVESTORS LP, and as
an Executive Committee Member of
VIKING LONG FUND GP LLC, on behalf of itself
and VIKING LONG FUND MASTER LTD.

/s/ DANIEL S. SUNDHEIM
By: Daniel S. Sundheim – individually and
as an Executive Committee Member of
VIKING GLOBAL PERFORMANCE LLC, on behalf
of itself and VIKING GLOBAL EQUITIES LP,
VIKING GLOBAL EQUITIES II LP and VGE III PORTFOLIO LTD.,
and as an Executive Committee Member of
Viking Global Partners LLC, on behalf of
VIKING GLOBAL INVESTORS LP, and as
an Executive Committee Member of
VIKING LONG FUND GP LLC, on behalf of itself
and VIKING LONG FUND MASTER LTD.

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