we derive substantially all of our gross profit from the following sources : commissions earned from facilitating reservations of accommodations , rental cars , cruises and other travel services ; transaction gross profit and customer processing fees from our accommodation , rental car , airline ticket and vacation package reservation services ; beginning on may 21 , 2013 , advertising revenues primarily earned by kayak from sending referrals to otcs and travel service providers , as well as from advertising placements on kayak 's websites and mobile apps ; beginning on july 24 , 2014 , revenues recognized by opentable , which consist of reservation revenues ( reservation fees paid by restaurants for diners seated through opentable 's online reservation service ) , subscription fees for restaurant reservation management services and other revenues ; and damage excess waiver fees , travel insurance fees and global distribution system ( `` gds `` ) reservation booking fees , in each case related to certain of our travel services . 40 our priceline.com brand offers merchant name your own price ® opaque travel services , which are recorded in revenue on a `` gross `` basis and have associated cost of revenue . all of our other services are recorded in revenue on a `` net `` basis and have no associated cost of revenue . therefore , revenue increases and decreases are impacted by changes in the mix of our revenues between name your own price ® travel services and other services . gross profit reflects the commission or net margin earned for all of our services . consequently , gross profit is an important measure to evaluate growth in our business because , in contrast to our revenues , it is not affected by the different methods of recording revenue and cost of revenue between our name your own price ® travel reservation services and our other services . trends over the last several years we have experienced strong growth in our accommodation reservation services . we believe this growth is the result of , among other things , the broader shift of travel purchases from offline to online , the widespread adoption of mobile devices , the high growth of travel overall in emerging markets such as asia-pacific and south america , and the continued innovation and execution by our teams around the world to build accommodation supply , content and distribution and to improve the consumer experience on our websites and mobile apps . these year-over-year growth rates have generally decelerated in recent years . for example , for the year ended december 31 , 2015 , our accommodation room night reservation growth was 25 % , a deceleration from 28 % in 2014 , 37 % in 2013 and 40 % in 2012. given the size of our hotel reservation business , we expect that our year-over-year growth rates will continue to decelerate , though the rate of deceleration may fluctuate . the size of the travel market outside of the united states is substantially greater than that within the united states . historically , internet use and e-commerce activity of international consumers have trailed that of consumers in the united states . however , international consumers are increasingly moving to online means for purchasing travel . accordingly , recent international online travel growth rates have substantially exceeded , and are expected to continue to exceed , the growth rates within the united states . we expect that over the long term , international online travel growth rates will follow a similar trend to that experienced in the united states . in addition , the base of hotel properties in europe and asia is particularly fragmented compared to that in the united states , where the hotel market is dominated by large hotel chains . we believe online reservation systems like ours may be more appealing to small chains and independent hotels more commonly found outside of the united states . we believe these trends and factors have enabled us to become the leading online accommodation reservation service provider in the world as measured by room nights booked . we believe that the opportunity to continue to grow our business exists for the markets in which we operate . our growth has primarily been generated by our worldwide accommodation reservation service brand , booking.com , which is our most significant brand , and has been due , in part , to the availability of a large and growing number of directly bookable properties through booking.com . booking.com included over 850,000 properties on its website as of february 15 , 2016 , which included approximately 390,000 vacation rental properties ( updated property counts are available on the booking.com website ) , and compares to over 635,000 properties ( including approximately 269,000 vacation rental properties ) a year ago . in september 2015 , booking.com changed the way it calculates property counts . as a result , properties that are contracted with booking.com but temporarily do not have availability on booking.com ( for example properties that are closed during their off-peak season or for renovations ) will remain included in booking.com 's property counts during these temporary periods . booking.com previously excluded properties that were temporarily unavailable for booking . we believe that continuously including them provides a more consistent and useful property count . we believe that continuing to expand the number and variety of accommodations available through our services , in particular booking.com , will help us to continue to grow our accommodation reservation business . as our international business represents the substantial majority of our financial results , we expect our operating results and other financial metrics to continue to be largely driven by international performance . story_separator_special_tag also , our consolidated results exclude intercompany advertising by our brands on kayak since our acquisition of kayak in may 2013. in 2015 , online advertising efficiency declined compared to the prior year , mainly due to lower rois . if google changes how it presents travel search results or the manner in which it conducts the auction for placement among search results in a manner that is competitively disadvantageous to us , whether to support its own travel-related services or otherwise , our ability to efficiently generate traffic to our websites could be harmed . see part i item 1a risk factors - `` we rely on online advertising channels to enhance our brand awareness and to generate a significant amount of traffic to our websites . `` and `` our business could be negatively affected by changes in internet search engine algorithms and dynamics or traffic-generating arrangements . `` the national competition authorities ( `` ncas `` ) of many governments have begun investigations into competitive practices within the online travel industry , and we may be involved or affected by such investigations and their results . various ncas , including those in france , germany , italy , austria , sweden , ireland and switzerland , opened investigations of booking.com 's contractual parity arrangements with accommodation providers in those jurisdictions , and a number of other ncas are looking at these issues . it is uncertain how these issues will finally be resolved . for example , the french , italian and swedish ncas accepted commitments offered by booking.com to resolve and close their investigations and booking.com 44 voluntarily implemented these commitments throughout the european economic area and switzerland on july 1 , 2015 , which resolved the concerns of various other countries . however , in august 2015 france adopted legislation known as the `` macron law `` making price parity agreements illegal , including those that had been approved by the french nca . for more information on these investigations and their potential effects on our business , see note 15 to our consolidated financial statements and part i item 1a risk factors - `` as the size of our business grows , we may become increasingly subject to the scrutiny of anti-trust and competition regulators . `` to the extent that regulatory authorities impose fines or require changes to our business practices or to those currently common to the industry or legislation is enacted with a similar effect , our business , competitive position and results of operations could be materially and adversely affected . negative publicity regarding any such investigations could adversely affect our brand and therefore our market share and results of operations . seasonality a meaningful amount of our gross bookings are generated early in the year , as customers plan and reserve their spring and summer vacations in europe and north america . from a cost perspective , we expense the substantial majority of our advertising activities as the expense is incurred , which is typically in the quarter in which reservations are booked . however , we generally do not recognize associated revenue until future quarters when the travel occurs . as a result , we have historically experienced our highest levels of profitability in the second and third quarters of the year , which is when we experience the highest levels of accommodation checkouts for the year for our european and north american businesses . we experience the highest levels of booking and travel consumption for our asia-pacific and south american businesses in the first and fourth quarters . as these businesses have generally been growing faster than our european and north american businesses , our operating results for the fourth quarter of the year have become more significant over time as a percentage of full year operating results . in addition , the date on which certain holidays fall can have an impact on our quarterly results . for example , in 2013 our second quarter year-over-year growth rates in revenue , gross profit , operating income and operating margins were adversely affected by easter falling in the first quarter instead of the second quarter , as it did in 2012. conversely , our second quarter 2014 year-over-year growth rates in revenue , gross profit , operating income and operating margins were favorably impacted by easter falling in the second quarter instead of the first quarter , as it did in 2013. similarly to 2013 , in 2016 easter will fall in the first quarter instead of the second quarter , and will therefore likely have a positive effect on our first quarter 2016 year-over-year growth rates and a negative effect on our second quarter 2016 year-over-year growth rates as compared to the same periods in 2015 when easter fell in the second quarter . the impact of seasonality can be exaggerated in the short term by the gross bookings growth rate of the business . for example , in periods where our growth rate substantially decelerates , our operating margins typically benefit from relatively less variable advertising expense . in addition , gross profit growth is typically less impacted in the near term due to the benefit of revenue related to reservations booked in previous quarters . other factors we believe that our future success depends in large part on our ability to continue to profitably grow our brands worldwide , and , over time , to offer other travel and travel-related services and further expand into other international markets . factors beyond our control , such as worldwide recession , oil prices , terrorist attacks , unusual weather patterns , natural disasters such as earthquakes , hurricanes , tsunamis , floods and volcanic eruptions , travel-related health concerns including pandemics and epidemics such as ebola , zika , influenza h1n1 , avian bird flu , sars and mers , political instability , regional hostilities , imposition of taxes or surcharges by regulatory authorities or travel-related

net cash used in investing activities was $ 3.9 billion for the year ended december 31 , 2015 . investing activities for the year ended december 31 , 2015 were affected by net purchases of investments of $ 3.6 billion , $ 140.3 million used for acquisitions , net of cash acquired , partially offset by net proceeds of $ 5.2 million for the settlement of foreign currency contracts . net cash used in investing activities was $ 2.3 billion for the year ended december 31 , 2014. investing activities for the year ended december 31 , 2014 were affected by payments of $ 2.5 billion for acquisitions , net of cash acquired , and net cash payments of $ 80.3 million for the settlement of foreign currency contracts slightly offset by net sales of investments of $ 350.3 million and a change in restricted cash of $ 9.3 million . cash invested in the purchase of property and equipment was $ 173.9 million and $ 131.5 million in the years ended december 31 , 2015 and 2014 , respectively . the increase in 2015 was related to additional data center capacity and new offices to support growth and geographic expansion , principally related to our booking.com business . net cash used in financing activities was $ 730.0 million for the year ended december 31 , 2015 .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```net cash used in investing activities was $ 3.9 billion for the year ended december 31 , 2015 . investing activities for the year ended december 31 , 2015 were affected by net purchases of investments of $ 3.6 billion , $ 140.3 million used for acquisitions , net of cash acquired , partially offset by net proceeds of $ 5.2 million for the settlement of foreign currency contracts . net cash used in investing activities was $ 2.3 billion for the year ended december 31 , 2014. investing activities for the year ended december 31 , 2014 were affected by payments of $ 2.5 billion for acquisitions , net of cash acquired , and net cash payments of $ 80.3 million for the settlement of foreign currency contracts slightly offset by net sales of investments of $ 350.3 million and a change in restricted cash of $ 9.3 million . cash invested in the purchase of property and equipment was $ 173.9 million and $ 131.5 million in the years ended december 31 , 2015 and 2014 , respectively . the increase in 2015 was related to additional data center capacity and new offices to support growth and geographic expansion , principally related to our booking.com business . net cash used in financing activities was $ 730.0 million for the year ended december 31 , 2015 .
```    
 Suspicious Activity Report : we derive substantially all of our gross profit from the following sources : commissions earned from facilitating reservations of accommodations , rental cars , cruises and other travel services ; transaction gross profit and customer processing fees from our accommodation , rental car , airline ticket and vacation package reservation services ; beginning on may 21 , 2013 , advertising revenues primarily earned by kayak from sending referrals to otcs and travel service providers , as well as from advertising placements on kayak 's websites and mobile apps ; beginning on july 24 , 2014 , revenues recognized by opentable , which consist of reservation revenues ( reservation fees paid by restaurants for diners seated through opentable 's online reservation service ) , subscription fees for restaurant reservation management services and other revenues ; and damage excess waiver fees , travel insurance fees and global distribution system ( `` gds `` ) reservation booking fees , in each case related to certain of our travel services . 40 our priceline.com brand offers merchant name your own price ® opaque travel services , which are recorded in revenue on a `` gross `` basis and have associated cost of revenue . all of our other services are recorded in revenue on a `` net `` basis and have no associated cost of revenue . therefore , revenue increases and decreases are impacted by changes in the mix of our revenues between name your own price ® travel services and other services . gross profit reflects the commission or net margin earned for all of our services . consequently , gross profit is an important measure to evaluate growth in our business because , in contrast to our revenues , it is not affected by the different methods of recording revenue and cost of revenue between our name your own price ® travel reservation services and our other services . trends over the last several years we have experienced strong growth in our accommodation reservation services . we believe this growth is the result of , among other things , the broader shift of travel purchases from offline to online , the widespread adoption of mobile devices , the high growth of travel overall in emerging markets such as asia-pacific and south america , and the continued innovation and execution by our teams around the world to build accommodation supply , content and distribution and to improve the consumer experience on our websites and mobile apps . these year-over-year growth rates have generally decelerated in recent years . for example , for the year ended december 31 , 2015 , our accommodation room night reservation growth was 25 % , a deceleration from 28 % in 2014 , 37 % in 2013 and 40 % in 2012. given the size of our hotel reservation business , we expect that our year-over-year growth rates will continue to decelerate , though the rate of deceleration may fluctuate . the size of the travel market outside of the united states is substantially greater than that within the united states . historically , internet use and e-commerce activity of international consumers have trailed that of consumers in the united states . however , international consumers are increasingly moving to online means for purchasing travel . accordingly , recent international online travel growth rates have substantially exceeded , and are expected to continue to exceed , the growth rates within the united states . we expect that over the long term , international online travel growth rates will follow a similar trend to that experienced in the united states . in addition , the base of hotel properties in europe and asia is particularly fragmented compared to that in the united states , where the hotel market is dominated by large hotel chains . we believe online reservation systems like ours may be more appealing to small chains and independent hotels more commonly found outside of the united states . we believe these trends and factors have enabled us to become the leading online accommodation reservation service provider in the world as measured by room nights booked . we believe that the opportunity to continue to grow our business exists for the markets in which we operate . our growth has primarily been generated by our worldwide accommodation reservation service brand , booking.com , which is our most significant brand , and has been due , in part , to the availability of a large and growing number of directly bookable properties through booking.com . booking.com included over 850,000 properties on its website as of february 15 , 2016 , which included approximately 390,000 vacation rental properties ( updated property counts are available on the booking.com website ) , and compares to over 635,000 properties ( including approximately 269,000 vacation rental properties ) a year ago . in september 2015 , booking.com changed the way it calculates property counts . as a result , properties that are contracted with booking.com but temporarily do not have availability on booking.com ( for example properties that are closed during their off-peak season or for renovations ) will remain included in booking.com 's property counts during these temporary periods . booking.com previously excluded properties that were temporarily unavailable for booking . we believe that continuously including them provides a more consistent and useful property count . we believe that continuing to expand the number and variety of accommodations available through our services , in particular booking.com , will help us to continue to grow our accommodation reservation business . as our international business represents the substantial majority of our financial results , we expect our operating results and other financial metrics to continue to be largely driven by international performance . story_separator_special_tag also , our consolidated results exclude intercompany advertising by our brands on kayak since our acquisition of kayak in may 2013. in 2015 , online advertising efficiency declined compared to the prior year , mainly due to lower rois . if google changes how it presents travel search results or the manner in which it conducts the auction for placement among search results in a manner that is competitively disadvantageous to us , whether to support its own travel-related services or otherwise , our ability to efficiently generate traffic to our websites could be harmed . see part i item 1a risk factors - `` we rely on online advertising channels to enhance our brand awareness and to generate a significant amount of traffic to our websites . `` and `` our business could be negatively affected by changes in internet search engine algorithms and dynamics or traffic-generating arrangements . `` the national competition authorities ( `` ncas `` ) of many governments have begun investigations into competitive practices within the online travel industry , and we may be involved or affected by such investigations and their results . various ncas , including those in france , germany , italy , austria , sweden , ireland and switzerland , opened investigations of booking.com 's contractual parity arrangements with accommodation providers in those jurisdictions , and a number of other ncas are looking at these issues . it is uncertain how these issues will finally be resolved . for example , the french , italian and swedish ncas accepted commitments offered by booking.com to resolve and close their investigations and booking.com 44 voluntarily implemented these commitments throughout the european economic area and switzerland on july 1 , 2015 , which resolved the concerns of various other countries . however , in august 2015 france adopted legislation known as the `` macron law `` making price parity agreements illegal , including those that had been approved by the french nca . for more information on these investigations and their potential effects on our business , see note 15 to our consolidated financial statements and part i item 1a risk factors - `` as the size of our business grows , we may become increasingly subject to the scrutiny of anti-trust and competition regulators . `` to the extent that regulatory authorities impose fines or require changes to our business practices or to those currently common to the industry or legislation is enacted with a similar effect , our business , competitive position and results of operations could be materially and adversely affected . negative publicity regarding any such investigations could adversely affect our brand and therefore our market share and results of operations . seasonality a meaningful amount of our gross bookings are generated early in the year , as customers plan and reserve their spring and summer vacations in europe and north america . from a cost perspective , we expense the substantial majority of our advertising activities as the expense is incurred , which is typically in the quarter in which reservations are booked . however , we generally do not recognize associated revenue until future quarters when the travel occurs . as a result , we have historically experienced our highest levels of profitability in the second and third quarters of the year , which is when we experience the highest levels of accommodation checkouts for the year for our european and north american businesses . we experience the highest levels of booking and travel consumption for our asia-pacific and south american businesses in the first and fourth quarters . as these businesses have generally been growing faster than our european and north american businesses , our operating results for the fourth quarter of the year have become more significant over time as a percentage of full year operating results . in addition , the date on which certain holidays fall can have an impact on our quarterly results . for example , in 2013 our second quarter year-over-year growth rates in revenue , gross profit , operating income and operating margins were adversely affected by easter falling in the first quarter instead of the second quarter , as it did in 2012. conversely , our second quarter 2014 year-over-year growth rates in revenue , gross profit , operating income and operating margins were favorably impacted by easter falling in the second quarter instead of the first quarter , as it did in 2013. similarly to 2013 , in 2016 easter will fall in the first quarter instead of the second quarter , and will therefore likely have a positive effect on our first quarter 2016 year-over-year growth rates and a negative effect on our second quarter 2016 year-over-year growth rates as compared to the same periods in 2015 when easter fell in the second quarter . the impact of seasonality can be exaggerated in the short term by the gross bookings growth rate of the business . for example , in periods where our growth rate substantially decelerates , our operating margins typically benefit from relatively less variable advertising expense . in addition , gross profit growth is typically less impacted in the near term due to the benefit of revenue related to reservations booked in previous quarters . other factors we believe that our future success depends in large part on our ability to continue to profitably grow our brands worldwide , and , over time , to offer other travel and travel-related services and further expand into other international markets . factors beyond our control , such as worldwide recession , oil prices , terrorist attacks , unusual weather patterns , natural disasters such as earthquakes , hurricanes , tsunamis , floods and volcanic eruptions , travel-related health concerns including pandemics and epidemics such as ebola , zika , influenza h1n1 , avian bird flu , sars and mers , political instability , regional hostilities , imposition of taxes or surcharges by regulatory authorities or travel-related

