we strive to be frugal with every expense , including capital expenditures and stock-based compensation . at the same time , we intend to continue to invest thoughtfully for long-term growth , with a focus on growing share in the markets we currently serve . we 've invested , and expect to continue to invest , in marketing to promote the redfin brand and in technology development to make the homebuying and home selling experience better and faster for our customers and our agents , while continuing to lower costs . our growth has been significant . for the years ended december 31 , 2015 , 2016 , and 2017 , we generated revenue of $ 187.3 million , $ 267.2 million , and $ 370.0 million , respectively , representing annual growth of 49 % , 43 % , and 38 % , respectively . we generated net losses of $ 30.2 million , $ 22.5 million , and $ 15.0 million for the years ended december 31 , 2015 , 2016 , and 2017 , respectively initial public offering on august 2 , 2017 , we completed our initial public offering , or ipo , in which we issued and sold 10,615,650 shares of our common stock ( including 1,384,650 shares pursuant to the underwriters ' option to purchase additional shares ) at a public offering price of $ 15.00 per share . the aggregate gross proceeds were approximately $ 159.2 million . we received $ 144.4 million in net proceeds after deducting $ 11.1 million of underwriting discounts and commissions and $ 3.7 million in offering costs . upon the closing of the ipo , all of the outstanding shares of our redeemable convertible preferred stock automatically converted into 55,422,002 shares of common stock on a one-for-one basis . subsequent to the closing of the ipo , there are no shares of redeemable convertible preferred stock outstanding . key business metrics in addition to the measures presented in our consolidated financial statements , we use the following key metrics to evaluate our business , develop financial forecasts , and make strategic decisions . 36 replace_table_token_5_th monthly average visitors the number of , and growth in , visitors to our website and mobile application are important leading indicators of our business activity because these channels are the primary ways we meet customers . for a particular period , monthly average visitors refers to the average of the number of unique visitors to our website and mobile application for each of the months in that period . monthly average visitors are influenced by market conditions that affect interest in buying or selling homes , the level and success of our marketing programs , and seasonality . we believe we can continue to increase monthly visitors , which helps our growth . given the lengthy process to buy or sell a home , a visitor during one month may not convert to a revenue-generating customer until many months later , if at all . when we refer to `` monthly average visitors `` for a particular period , we are referring to the average number of unique visitors to our website and our mobile application for each of the months in that period , as measured by google analytics , a product that provides digital marketing intelligence . visitors are tracked by google analytics using cookies , with a unique cookie being assigned to each browser or mobile application on a device . for any given month , we count all of the unique cookies that visited our website or either our ios or android mobile application during that month ; each such unique cookie is a unique visitor . if a person accesses our mobile application using different devices within a given month , each such mobile device is counted as a separate visitor for that month . if the same person accesses our website using an anonymous browser , or clears or resets cookies on his or her device , each access with a new cookie is counted as a new unique visitor for that month . real estate transactions increasing the number of real estate transactions in which we or our partner agents represent homebuyers and home sellers is critical to increasing our revenue and , in turn , to achieving profitability . real estate transaction volume is influenced by the pricing and quality of our services as well as market conditions that affect home sales , such as local inventory levels and mortgage interest rates . real estate transaction volume is also affected by seasonality and macroeconomic factors . we include a single transaction twice when we or our partner agents serve both the homebuyer and the home seller of a home . 37 real estate revenue per real estate transaction real estate revenue per real estate transaction , together with the number of real estate transactions , is a factor in evaluating business growth and determining pricing . changes in revenue per real estate transaction can be affected by our pricing , the mix of transactions from homebuyers and home sellers , changes in the value of homes in the markets we serve , the geographic mix of our transactions , and the transactions we refer to partner agents . we generally generate more revenue per real estate transaction from representing homebuyers than home sellers . from 2015 through 2017 , the percentage of brokerage transactions from home sellers increased from slightly over 25 % to slightly over 35 % . we expect this trend to continue , because we believe that representing homes sellers has unique strategic value , including the marketing power of yard signs and digital marketing campaigns , and the market effect of controlling listing inventory . to keep revenue per brokerage transactions about the same from year to year , we expect to reduce our commission refund to homebuyers as more of our brokerage transactions come from home sellers . story_separator_special_tag story_separator_special_tag beginning in mid-2017 and lasting through 2027. our purchase obligations primarily relate to the noncancelable portion of commitments related to our network infrastructure and annual employee meeting . we do not include in the table above obligations under contracts that we can cancel without significant penalty . we also include the purchase prices of homes that we are under contract to purchase through redfin now but that have not yet closed . there were three such homes as of december 31 , 2017. critical accounting policies and estimates discussion and analysis of our financial condition and results of operations are based on our financial statements , which have been prepared in accordance with gaap . preparing these financial statements requires us to make estimates and judgments that affect the reported amounts of assets and liabilities and related disclosure of contingent assets and liabilities , revenue , and expenses at the date of 49 the financial statements . generally , we base our estimates on historical experience and on various other assumptions in accordance with gaap that we believe to be reasonable under the circumstances . actual results may differ from these estimates under different assumptions or conditions . critical accounting policies and estimates are those that we consider the most important to the portrayal of our financial condition and results of operations because they require our most difficult , subjective , or complex judgments , often as a result of the need to make estimates about the effect of matters that are inherently uncertain . our critical accounting policies and estimates include those related to revenue recognition and stock-based compensation . revenue recognition revenue primarily consists of commissions and fees charged on each real estate transaction completed by us or our partner agents . we recognize commission-based brokerage revenue upon closing of a real estate transaction , net of any commission refund , closing-cost adjustment , commission discount or transaction fee adjustment . partner revenue consists of fees earned by referring customers to partner agents . partner revenue is earned and recognized when partner agents close a referred transaction , net of any refund provided to customers . revenue earned from selling homes previously purchased by redfin now is recorded at closing on a gross basis , representing the sales price of the home . revenue earned but not received is recorded as accrued revenue on the accompanying consolidated balance sheets . fees and revenue from other services are recognized when the service is provided . we have completed our analysis of the new revenue standard , revenue from contracts with customers ( topic 606 ) , and determined the adoption will not have a material impact on our financial statements . for further discussion of the new revenue standard , please see note 1 to our consolidated financial statements included elsewhere in annual report on form 10-k. stock-based compensation stock-based compensation is measured at the grant date based on the fair value of the award and is recognized as expense , net of estimated forfeitures , over the requisite service period , which is generally the vesting period of the respective award . determining the fair value of stock options at the grant date is highly complex and subjective and requires significant judgment . we use the black-scholes-merton option-pricing model to determine the fair value of stock options , the output of which is affected by a number of variables . these variables include the fair value of our common stock , our expected common stock price volatility over the expected life of the options , expected term of the stock option , risk-free interest rates and expected dividends , which are estimated as follows : fair value of our common stock . prior to our ipo , the fair value of the shares of our common stock underlying stock options was established by our board of directors with the assistance of an independent third-party valuation firm . because there was no public market for our common stock , our board of directors has relied on this independent valuation and other factors to establish the fair value of our common stock at the time of grant of the option . expected life . the expected term was estimated using the simplified method allowed under sec guidance . volatility . prior to our ipo , the expected stock price volatility for our common stock was estimated by taking the average historical price volatility for industry peers based on daily price observations . industry peers consist of several public companies in the real estate brokerage and technology industries . in 2015 , we changed the group of industry peers due to external mergers and acquisitions in the real estate industry . 50 risk-free rate . the risk-free interest rate is based on the yields of u.s. treasury securities with maturities similar to the expected term of the options for each option group . dividend yield . we have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future . consequently , we used an expected dividend yield of zero . on january 1 , 2017 , we adopted accounting standards update , or asu , 2016-09 and elected to book forfeitures as they occur , using the modified retrospective approach through a cumulative-effect adjustment of approximately $ 0.5 million to beginning accumulative deficit . the adoption of this guidance did not have a material impact on our financial position , results of operations or cash flows . in late 2017 , we began issuing restricted stock units ( rsus ) as the primary form of equity compensation for our employees . compensation cost for restricted stock units is measured at the fair value on the grant date and recognized as expense over the related service period . valuation of common stock and redeemable convertible preferred stock prior to our ipo , given the absence of a public trading market for

liquidity and capital resources 47 on august 2 , 2017 , we closed our ipo of 10,615,650 shares of our common stock at a public offering price of $ 15.00 per share . we received approximately $ 144.4 million in net proceeds after deducting underwriting discounts and commission , and offering costs . prior to our ipo , our principal sources of liquidity were the net proceeds we received through private sales of our equity securities . from our inception through our ipo , we completed several rounds of sales of shares of our redeemable convertible preferred stock to investors , with total gross proceeds of approximately $ 167.5 million . in the first quarter of 2017 , we introduced redfin mortgage to originate and underwrite mortgage loans , and began testing a new service called redfin now , where we buy homes directly from home sellers , intending to resell those homes . to date , neither business has had a material impact on our liquidity . as of december 31 , 2017 , we held $ 3.4 million of home inventory . if we decide to significantly expand these new product offerings , we may seek to raise additional capital through equity , equity-linked , or debt-financing arrangements to fund this expansion . we can not assure you that any additional financing will be available to us on acceptable terms or at all . cash flows the following table summarizes our cash flows for the periods indicated : replace_table_token_21_th cash flows from operating activities net cash provided by operating activities in 2017 consisted of $ 15.0 million of net losses , an $ 18.3 million positive impact from non-cash items , an $ 8.4 million reduction in miscellaneous receivables when the landlord for our seattle headquarters office reimbursed us for tenant improvements , and a $ 4.9


 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.
     ```liquidity and capital resources 47 on august 2 , 2017 , we closed our ipo of 10,615,650 shares of our common stock at a public offering price of $ 15.00 per share . we received approximately $ 144.4 million in net proceeds after deducting underwriting discounts and commission , and offering costs . prior to our ipo , our principal sources of liquidity were the net proceeds we received through private sales of our equity securities . from our inception through our ipo , we completed several rounds of sales of shares of our redeemable convertible preferred stock to investors , with total gross proceeds of approximately $ 167.5 million . in the first quarter of 2017 , we introduced redfin mortgage to originate and underwrite mortgage loans , and began testing a new service called redfin now , where we buy homes directly from home sellers , intending to resell those homes . to date , neither business has had a material impact on our liquidity . as of december 31 , 2017 , we held $ 3.4 million of home inventory . if we decide to significantly expand these new product offerings , we may seek to raise additional capital through equity , equity-linked , or debt-financing arrangements to fund this expansion . we can not assure you that any additional financing will be available to us on acceptable terms or at all . cash flows the following table summarizes our cash flows for the periods indicated : replace_table_token_21_th cash flows from operating activities net cash provided by operating activities in 2017 consisted of $ 15.0 million of net losses , an $ 18.3 million positive impact from non-cash items , an $ 8.4 million reduction in miscellaneous receivables when the landlord for our seattle headquarters office reimbursed us for tenant improvements , and a $ 4.9
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 Suspicious Activity Report : we strive to be frugal with every expense , including capital expenditures and stock-based compensation . at the same time , we intend to continue to invest thoughtfully for long-term growth , with a focus on growing share in the markets we currently serve . we 've invested , and expect to continue to invest , in marketing to promote the redfin brand and in technology development to make the homebuying and home selling experience better and faster for our customers and our agents , while continuing to lower costs . our growth has been significant . for the years ended december 31 , 2015 , 2016 , and 2017 , we generated revenue of $ 187.3 million , $ 267.2 million , and $ 370.0 million , respectively , representing annual growth of 49 % , 43 % , and 38 % , respectively . we generated net losses of $ 30.2 million , $ 22.5 million , and $ 15.0 million for the years ended december 31 , 2015 , 2016 , and 2017 , respectively initial public offering on august 2 , 2017 , we completed our initial public offering , or ipo , in which we issued and sold 10,615,650 shares of our common stock ( including 1,384,650 shares pursuant to the underwriters ' option to purchase additional shares ) at a public offering price of $ 15.00 per share . the aggregate gross proceeds were approximately $ 159.2 million . we received $ 144.4 million in net proceeds after deducting $ 11.1 million of underwriting discounts and commissions and $ 3.7 million in offering costs . upon the closing of the ipo , all of the outstanding shares of our redeemable convertible preferred stock automatically converted into 55,422,002 shares of common stock on a one-for-one basis . subsequent to the closing of the ipo , there are no shares of redeemable convertible preferred stock outstanding . key business metrics in addition to the measures presented in our consolidated financial statements , we use the following key metrics to evaluate our business , develop financial forecasts , and make strategic decisions . 36 replace_table_token_5_th monthly average visitors the number of , and growth in , visitors to our website and mobile application are important leading indicators of our business activity because these channels are the primary ways we meet customers . for a particular period , monthly average visitors refers to the average of the number of unique visitors to our website and mobile application for each of the months in that period . monthly average visitors are influenced by market conditions that affect interest in buying or selling homes , the level and success of our marketing programs , and seasonality . we believe we can continue to increase monthly visitors , which helps our growth . given the lengthy process to buy or sell a home , a visitor during one month may not convert to a revenue-generating customer until many months later , if at all . when we refer to `` monthly average visitors `` for a particular period , we are referring to the average number of unique visitors to our website and our mobile application for each of the months in that period , as measured by google analytics , a product that provides digital marketing intelligence . visitors are tracked by google analytics using cookies , with a unique cookie being assigned to each browser or mobile application on a device . for any given month , we count all of the unique cookies that visited our website or either our ios or android mobile application during that month ; each such unique cookie is a unique visitor . if a person accesses our mobile application using different devices within a given month , each such mobile device is counted as a separate visitor for that month . if the same person accesses our website using an anonymous browser , or clears or resets cookies on his or her device , each access with a new cookie is counted as a new unique visitor for that month . real estate transactions increasing the number of real estate transactions in which we or our partner agents represent homebuyers and home sellers is critical to increasing our revenue and , in turn , to achieving profitability . real estate transaction volume is influenced by the pricing and quality of our services as well as market conditions that affect home sales , such as local inventory levels and mortgage interest rates . real estate transaction volume is also affected by seasonality and macroeconomic factors . we include a single transaction twice when we or our partner agents serve both the homebuyer and the home seller of a home . 37 real estate revenue per real estate transaction real estate revenue per real estate transaction , together with the number of real estate transactions , is a factor in evaluating business growth and determining pricing . changes in revenue per real estate transaction can be affected by our pricing , the mix of transactions from homebuyers and home sellers , changes in the value of homes in the markets we serve , the geographic mix of our transactions , and the transactions we refer to partner agents . we generally generate more revenue per real estate transaction from representing homebuyers than home sellers . from 2015 through 2017 , the percentage of brokerage transactions from home sellers increased from slightly over 25 % to slightly over 35 % . we expect this trend to continue , because we believe that representing homes sellers has unique strategic value , including the marketing power of yard signs and digital marketing campaigns , and the market effect of controlling listing inventory . to keep revenue per brokerage transactions about the same from year to year , we expect to reduce our commission refund to homebuyers as more of our brokerage transactions come from home sellers . story_separator_special_tag story_separator_special_tag beginning in mid-2017 and lasting through 2027. our purchase obligations primarily relate to the noncancelable portion of commitments related to our network infrastructure and annual employee meeting . we do not include in the table above obligations under contracts that we can cancel without significant penalty . we also include the purchase prices of homes that we are under contract to purchase through redfin now but that have not yet closed . there were three such homes as of december 31 , 2017. critical accounting policies and estimates discussion and analysis of our financial condition and results of operations are based on our financial statements , which have been prepared in accordance with gaap . preparing these financial statements requires us to make estimates and judgments that affect the reported amounts of assets and liabilities and related disclosure of contingent assets and liabilities , revenue , and expenses at the date of 49 the financial statements . generally , we base our estimates on historical experience and on various other assumptions in accordance with gaap that we believe to be reasonable under the circumstances . actual results may differ from these estimates under different assumptions or conditions . critical accounting policies and estimates are those that we consider the most important to the portrayal of our financial condition and results of operations because they require our most difficult , subjective , or complex judgments , often as a result of the need to make estimates about the effect of matters that are inherently uncertain . our critical accounting policies and estimates include those related to revenue recognition and stock-based compensation . revenue recognition revenue primarily consists of commissions and fees charged on each real estate transaction completed by us or our partner agents . we recognize commission-based brokerage revenue upon closing of a real estate transaction , net of any commission refund , closing-cost adjustment , commission discount or transaction fee adjustment . partner revenue consists of fees earned by referring customers to partner agents . partner revenue is earned and recognized when partner agents close a referred transaction , net of any refund provided to customers . revenue earned from selling homes previously purchased by redfin now is recorded at closing on a gross basis , representing the sales price of the home . revenue earned but not received is recorded as accrued revenue on the accompanying consolidated balance sheets . fees and revenue from other services are recognized when the service is provided . we have completed our analysis of the new revenue standard , revenue from contracts with customers ( topic 606 ) , and determined the adoption will not have a material impact on our financial statements . for further discussion of the new revenue standard , please see note 1 to our consolidated financial statements included elsewhere in annual report on form 10-k. stock-based compensation stock-based compensation is measured at the grant date based on the fair value of the award and is recognized as expense , net of estimated forfeitures , over the requisite service period , which is generally the vesting period of the respective award . determining the fair value of stock options at the grant date is highly complex and subjective and requires significant judgment . we use the black-scholes-merton option-pricing model to determine the fair value of stock options , the output of which is affected by a number of variables . these variables include the fair value of our common stock , our expected common stock price volatility over the expected life of the options , expected term of the stock option , risk-free interest rates and expected dividends , which are estimated as follows : fair value of our common stock . prior to our ipo , the fair value of the shares of our common stock underlying stock options was established by our board of directors with the assistance of an independent third-party valuation firm . because there was no public market for our common stock , our board of directors has relied on this independent valuation and other factors to establish the fair value of our common stock at the time of grant of the option . expected life . the expected term was estimated using the simplified method allowed under sec guidance . volatility . prior to our ipo , the expected stock price volatility for our common stock was estimated by taking the average historical price volatility for industry peers based on daily price observations . industry peers consist of several public companies in the real estate brokerage and technology industries . in 2015 , we changed the group of industry peers due to external mergers and acquisitions in the real estate industry . 50 risk-free rate . the risk-free interest rate is based on the yields of u.s. treasury securities with maturities similar to the expected term of the options for each option group . dividend yield . we have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future . consequently , we used an expected dividend yield of zero . on january 1 , 2017 , we adopted accounting standards update , or asu , 2016-09 and elected to book forfeitures as they occur , using the modified retrospective approach through a cumulative-effect adjustment of approximately $ 0.5 million to beginning accumulative deficit . the adoption of this guidance did not have a material impact on our financial position , results of operations or cash flows . in late 2017 , we began issuing restricted stock units ( rsus ) as the primary form of equity compensation for our employees . compensation cost for restricted stock units is measured at the fair value on the grant date and recognized as expense over the related service period . valuation of common stock and redeemable convertible preferred stock prior to our ipo , given the absence of a public trading market for

