for example , we compete with a number of companies in each of our key end markets . this includes companies that are much larger than we are and smaller companies 34 that focus on a particular niche . although we believe we are well-positioned in each of our key end markets and seek to differentiate ourselves from our competitors , competition remains intense and profitably growing our revenues has been challenging . for example , revenue in our ims business was negatively impacted in 2018 by parts shortages and delays in new program ramps caused by customer design changes , yield issues and other factors . these factors , together with unfavorable program mix , under absorption of labor and overhead costs , and high fixed costs associated with new program ramps caused gross margins for our ims business to decline from 7.2 % in 2017 to 6.0 % in 2018. additionally , gross margins for our cps business decreased from 8.9 % in 2017 to 8.1 % in 2018 and continue to be well below our expectations for this business . we continue to address these challenges on both a short-term and long-term basis . however , we expect the supply constrained environment to continue through at least the first half of calendar 2019. a small number of customers have historically generated a significant portion of our net sales . sales to our ten largest customers typically represent approximately 50 % of our net sales . a single customer represented 10 % or more of our net sales in 2018 and 2016 and two customers each represented 10 % or more of our net sales in 2017. we typically generate about 80 % of our net sales from products manufactured in our foreign operations . the concentration of foreign operations has resulted primarily from a desire on the part of many of our customers to manufacture in lower cost locations in regions such as asia , latin america and eastern europe . historically , we have had substantial recurring sales to existing customers . we typically enter into supply agreements with our major oem customers . these agreements generally have terms ranging from three to five years and cover the manufacture of a range of products . under these agreements , a customer typically agrees to purchase its requirements for specific products in particular geographic areas from us . however , these agreements generally do not obligate the customer to purchase minimum quantities of products , which can have the effect of reducing revenue and profitability . in addition , some customer contracts contain cost reduction objectives , which can have the effect of reducing revenue from such customers . both the u.s. and china have recently imposed tariffs impacting certain products imported into such countries . although our customers are generally liable to us for reimbursement of tariffs we pay on components imported for the manufacture of their products , there can be no assurance that we will be successful in recovering all of the tariffs that are owed to us . unrecovered tariffs paid on behalf of our customers reduce our gross margins . we do not expect the net impact of tariffs , after recovery from customers , to be material . also , although we are required to pay tariffs upon importation of the components , we may not recover these amounts from customers until some time later , which adversely impacts our operating cash flow in a given period . 35 critical accounting policies and estimates management 's discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements which have been prepared in accordance with accounting principles generally accepted in the united states . we review the accounting policies used in reporting our financial results on a regular basis . the preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets , liabilities , net sales and expenses and related disclosure of contingent liabilities . on an ongoing basis , we evaluate the process used to develop estimates for certain reserves and contingent liabilities , including those related to product returns , accounts receivable , inventories , income taxes , warranty obligations , environmental matters , contingencies and litigation . we base our estimates on historical experience and various other assumptions that we believe are reasonable for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources . our actual results may differ materially from these estimates . we believe the following critical accounting policies reflect the more significant judgments and estimates used by us in preparing our consolidated financial statements : accounts receivable and other related allowances— we estimate uncollectible accounts , product returns and other adjustments related to current period net sales to establish valuation allowances . in making these estimates , we analyze the creditworthiness of our customers , past experience , specific facts and circumstances , and the overall economic climate in the industries we serve . if actual uncollectible accounts , product returns or other adjustments differ significantly from our estimates , the amount of sales or operating expenses we report could be affected . the ultimate realization of our accounts receivable is a significant credit risk . this risk is mitigated by ( i ) making a significant portion of sales to financially sound companies , ( ii ) ongoing credit evaluation of our customers , ( iii ) frequent contact with our customers , especially our most significant customers , which enables us to monitor changes in their business operations and to respond accordingly and ( iv ) obtaining , in certain cases , a guaranty from a customer 's parent entity when our customer is not the ultimate parent entity or a letter of credit from the customer 's bank . story_separator_special_tag the following table summarizes the primary components of other income , net ( in thousands ) : replace_table_token_9_th provision for ( benefit from ) income taxes we recorded income tax expense of $ 193.1 million , $ 74.6 million and $ 16.8 million in 2018 , 2017 and 2016 , respectively . our effective tax rates were 197.9 % , 35.0 % and 8.2 % for 2018 , 2017 and 2016 , respectively . income tax expense for 2018 was $ 118.4 million higher than income tax expense for 2017 , despite a decrease in pre-tax income of $ 115.9 million in 2018. this was primarily attributable to the impact of the tax act , which increased income tax expense approximately $ 161 million because of a non-cash reduction in the carrying value of our net deferred tax assets , partially offset by a decrease in the us tax rate from 35 % to 21 % , and a $ 4.8 million discrete tax benefit resulting from a settlement with a foreign tax authority in the third quarter of 2018. income tax expense for 2017 was $ 57.8 million higher than income tax expense for 2016 , despite an increase in pre-tax income of only $ 8.9 million in 2017. this was due primarily to a $ 96.2 million release of our deferred tax assets valuation allowance in 2016 , partially offset by $ 17.3 million of income tax expense in 2016 associated with an increase to our deferred tax liability for undistributed foreign earnings of a certain foreign subsidiary . these two items represent a net change of $ 78.9 million . this change was partially offset in 2017 by a discrete tax benefit that was recorded in 2017 resulting from the merger of two foreign entities , the surviving entity of which was , and continues to be , included in our u.s. federal consolidated tax group . this restructuring allowed us to recognize a u.s. deferred tax asset to reflect the federal deductibility of a foreign uncertain tax position that became recognizable upon the merger of the subsidiaries . the tax provision for 2016 was lower than the amount expected if the federal statutory tax rate of 35 % was applied primarily due to a release of our deferred tax assets valuation allowance of $ 96.2 million . a valuation allowance is established or maintained when , based on currently available information and other factors , it is more likely than not that all or a portion of the deferred tax assets will not be realized . we regularly assess our valuation allowance against deferred tax assets on a jurisdiction by jurisdiction basis . we consider all available positive and negative evidence , including future reversals of temporary differences , projected future taxable income , tax planning strategies and 41 recent financial results . significant judgment is required in assessing our ability to generate revenue , gross profit , operating income and jurisdictional taxable income in future periods . as of october 1 , 2016 , we had released all of our u.s. federal valuation allowance . liquidity and capital resources replace_table_token_10_th key working capital management measures replace_table_token_11_th ( 1 ) days sales outstanding ( a measure of how quickly we collect our accounts receivable ) , or `` dso `` , is calculated as the ratio of average accounts receivable , net , to average daily net sales for the quarter . ( 2 ) inventory turns ( annualized ) are calculated as the ratio of four times our cost of sales for the quarter to average inventory . ( 3 ) days inventory on hand is calculated as the ratio of average inventory for the quarter to average daily cost of sales for the quarter . ( 4 ) accounts payable days ( a measure of how quickly we pay our suppliers ) , or `` dpo `` , is calculated as the ratio of 365 days to accounts payable turns , in which accounts payable turns is calculated as the ratio of four times our cost of sales for the quarter to average accounts payable . ( 5 ) cash cycle days is calculated as days inventory on hand plus days sales outstanding minus accounts payable days . story_separator_special_tag board of directors has authorized us to repurchase shares of our common stock , subject to a dollar limitation . the timing of repurchases will depend upon capital needs to support the growth of our business , market conditions and other factors . although stock repurchases are intended to increase stockholder value , purchases of shares reduce our liquidity . we repurchased 5.0 million and 4.3 million shares of our common stock for $ 146 million and $ 160 million in the open market in 2018 and 2017 , respectively . as of september 29 , 2018 , subject to limitations on stock repurchases contained in our debt agreements , $ 108 million remains available under programs authorized by the board of directors , none of which is subject to an expiration date . during 2018 , we entered into a receivables purchase agreement ( the “ rpa ” ) with certain third-party banking institutions for the sale of trade receivables generated from sales to certain customers . a maximum of $ 540 million of sold receivables can be outstanding at any point in time under this program , subject to limitations under our amended cash flow revolver . trade receivables sold pursuant to the rpa are serviced by us . in addition to the rpa , we have the option to participate in trade receivables sales programs that have been implemented by certain of our customers , as in effect from time to time . we do not service trade receivables sold under these other programs . under each of the programs noted above , we sell our entire interest in a trade receivable for 100 % of face value , less a discount

cash and cash equivalents were $ 420 million at september 29 , 2018 and $ 407 million at september 30 , 2017 . our cash levels vary during any given period depending on the timing of collections from customers and payments to suppliers , borrowings under credit facilities , repurchases of capital stock and other factors . our working capital was approximately $ 0.6 billion and $ 1 billion at september 29 , 2018 and september 30 , 2017 , respectively . the reduction in net working capital resulted primarily from the reclassification of our secured notes due in 2019 from long-term debt to current debt . we are currently in the process of refinancing these notes and expect to complete this refinancing upon maturity of the notes . net cash provided by operating activities was $ 156 million , $ 251 million and $ 390 million for 2018 , 2017 and 2016 , respectively . cash flows from operating activities consists of : ( 1 ) net income adjusted to exclude non-cash items such as depreciation and amortization , deferred income taxes and stock-based compensation expense and ( 2 ) changes in net operating assets , which are comprised of accounts receivable , inventories , prepaid expenses and other assets , accounts payable and accrued liabilities . our working capital metrics tend to fluctuate from quarter-to-quarter based on factors such as the linearity of our shipments to customers and purchases from suppliers , customer and supplier mix , and the negotiation of payment terms with customers and suppliers . these fluctuations can significantly affect our cash flows from operating activities . 42 during 2018 , we generated $ 262 million of cash from earnings , excluding non-cash items , and used $ 106 million of cash in connection with an increase in our net operating assets , resulting primarily from an increase in inventories and accounts receivable of $ 324 million and $ 69 million , respectively , partially offset by an increase in accounts payable of $ 268 million .


 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.
     ```cash and cash equivalents were $ 420 million at september 29 , 2018 and $ 407 million at september 30 , 2017 . our cash levels vary during any given period depending on the timing of collections from customers and payments to suppliers , borrowings under credit facilities , repurchases of capital stock and other factors . our working capital was approximately $ 0.6 billion and $ 1 billion at september 29 , 2018 and september 30 , 2017 , respectively . the reduction in net working capital resulted primarily from the reclassification of our secured notes due in 2019 from long-term debt to current debt . we are currently in the process of refinancing these notes and expect to complete this refinancing upon maturity of the notes . net cash provided by operating activities was $ 156 million , $ 251 million and $ 390 million for 2018 , 2017 and 2016 , respectively . cash flows from operating activities consists of : ( 1 ) net income adjusted to exclude non-cash items such as depreciation and amortization , deferred income taxes and stock-based compensation expense and ( 2 ) changes in net operating assets , which are comprised of accounts receivable , inventories , prepaid expenses and other assets , accounts payable and accrued liabilities . our working capital metrics tend to fluctuate from quarter-to-quarter based on factors such as the linearity of our shipments to customers and purchases from suppliers , customer and supplier mix , and the negotiation of payment terms with customers and suppliers . these fluctuations can significantly affect our cash flows from operating activities . 42 during 2018 , we generated $ 262 million of cash from earnings , excluding non-cash items , and used $ 106 million of cash in connection with an increase in our net operating assets , resulting primarily from an increase in inventories and accounts receivable of $ 324 million and $ 69 million , respectively , partially offset by an increase in accounts payable of $ 268 million .
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 Suspicious Activity Report : for example , we compete with a number of companies in each of our key end markets . this includes companies that are much larger than we are and smaller companies 34 that focus on a particular niche . although we believe we are well-positioned in each of our key end markets and seek to differentiate ourselves from our competitors , competition remains intense and profitably growing our revenues has been challenging . for example , revenue in our ims business was negatively impacted in 2018 by parts shortages and delays in new program ramps caused by customer design changes , yield issues and other factors . these factors , together with unfavorable program mix , under absorption of labor and overhead costs , and high fixed costs associated with new program ramps caused gross margins for our ims business to decline from 7.2 % in 2017 to 6.0 % in 2018. additionally , gross margins for our cps business decreased from 8.9 % in 2017 to 8.1 % in 2018 and continue to be well below our expectations for this business . we continue to address these challenges on both a short-term and long-term basis . however , we expect the supply constrained environment to continue through at least the first half of calendar 2019. a small number of customers have historically generated a significant portion of our net sales . sales to our ten largest customers typically represent approximately 50 % of our net sales . a single customer represented 10 % or more of our net sales in 2018 and 2016 and two customers each represented 10 % or more of our net sales in 2017. we typically generate about 80 % of our net sales from products manufactured in our foreign operations . the concentration of foreign operations has resulted primarily from a desire on the part of many of our customers to manufacture in lower cost locations in regions such as asia , latin america and eastern europe . historically , we have had substantial recurring sales to existing customers . we typically enter into supply agreements with our major oem customers . these agreements generally have terms ranging from three to five years and cover the manufacture of a range of products . under these agreements , a customer typically agrees to purchase its requirements for specific products in particular geographic areas from us . however , these agreements generally do not obligate the customer to purchase minimum quantities of products , which can have the effect of reducing revenue and profitability . in addition , some customer contracts contain cost reduction objectives , which can have the effect of reducing revenue from such customers . both the u.s. and china have recently imposed tariffs impacting certain products imported into such countries . although our customers are generally liable to us for reimbursement of tariffs we pay on components imported for the manufacture of their products , there can be no assurance that we will be successful in recovering all of the tariffs that are owed to us . unrecovered tariffs paid on behalf of our customers reduce our gross margins . we do not expect the net impact of tariffs , after recovery from customers , to be material . also , although we are required to pay tariffs upon importation of the components , we may not recover these amounts from customers until some time later , which adversely impacts our operating cash flow in a given period . 35 critical accounting policies and estimates management 's discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements which have been prepared in accordance with accounting principles generally accepted in the united states . we review the accounting policies used in reporting our financial results on a regular basis . the preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets , liabilities , net sales and expenses and related disclosure of contingent liabilities . on an ongoing basis , we evaluate the process used to develop estimates for certain reserves and contingent liabilities , including those related to product returns , accounts receivable , inventories , income taxes , warranty obligations , environmental matters , contingencies and litigation . we base our estimates on historical experience and various other assumptions that we believe are reasonable for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources . our actual results may differ materially from these estimates . we believe the following critical accounting policies reflect the more significant judgments and estimates used by us in preparing our consolidated financial statements : accounts receivable and other related allowances— we estimate uncollectible accounts , product returns and other adjustments related to current period net sales to establish valuation allowances . in making these estimates , we analyze the creditworthiness of our customers , past experience , specific facts and circumstances , and the overall economic climate in the industries we serve . if actual uncollectible accounts , product returns or other adjustments differ significantly from our estimates , the amount of sales or operating expenses we report could be affected . the ultimate realization of our accounts receivable is a significant credit risk . this risk is mitigated by ( i ) making a significant portion of sales to financially sound companies , ( ii ) ongoing credit evaluation of our customers , ( iii ) frequent contact with our customers , especially our most significant customers , which enables us to monitor changes in their business operations and to respond accordingly and ( iv ) obtaining , in certain cases , a guaranty from a customer 's parent entity when our customer is not the ultimate parent entity or a letter of credit from the customer 's bank . story_separator_special_tag the following table summarizes the primary components of other income , net ( in thousands ) : replace_table_token_9_th provision for ( benefit from ) income taxes we recorded income tax expense of $ 193.1 million , $ 74.6 million and $ 16.8 million in 2018 , 2017 and 2016 , respectively . our effective tax rates were 197.9 % , 35.0 % and 8.2 % for 2018 , 2017 and 2016 , respectively . income tax expense for 2018 was $ 118.4 million higher than income tax expense for 2017 , despite a decrease in pre-tax income of $ 115.9 million in 2018. this was primarily attributable to the impact of the tax act , which increased income tax expense approximately $ 161 million because of a non-cash reduction in the carrying value of our net deferred tax assets , partially offset by a decrease in the us tax rate from 35 % to 21 % , and a $ 4.8 million discrete tax benefit resulting from a settlement with a foreign tax authority in the third quarter of 2018. income tax expense for 2017 was $ 57.8 million higher than income tax expense for 2016 , despite an increase in pre-tax income of only $ 8.9 million in 2017. this was due primarily to a $ 96.2 million release of our deferred tax assets valuation allowance in 2016 , partially offset by $ 17.3 million of income tax expense in 2016 associated with an increase to our deferred tax liability for undistributed foreign earnings of a certain foreign subsidiary . these two items represent a net change of $ 78.9 million . this change was partially offset in 2017 by a discrete tax benefit that was recorded in 2017 resulting from the merger of two foreign entities , the surviving entity of which was , and continues to be , included in our u.s. federal consolidated tax group . this restructuring allowed us to recognize a u.s. deferred tax asset to reflect the federal deductibility of a foreign uncertain tax position that became recognizable upon the merger of the subsidiaries . the tax provision for 2016 was lower than the amount expected if the federal statutory tax rate of 35 % was applied primarily due to a release of our deferred tax assets valuation allowance of $ 96.2 million . a valuation allowance is established or maintained when , based on currently available information and other factors , it is more likely than not that all or a portion of the deferred tax assets will not be realized . we regularly assess our valuation allowance against deferred tax assets on a jurisdiction by jurisdiction basis . we consider all available positive and negative evidence , including future reversals of temporary differences , projected future taxable income , tax planning strategies and 41 recent financial results . significant judgment is required in assessing our ability to generate revenue , gross profit , operating income and jurisdictional taxable income in future periods . as of october 1 , 2016 , we had released all of our u.s. federal valuation allowance . liquidity and capital resources replace_table_token_10_th key working capital management measures replace_table_token_11_th ( 1 ) days sales outstanding ( a measure of how quickly we collect our accounts receivable ) , or `` dso `` , is calculated as the ratio of average accounts receivable , net , to average daily net sales for the quarter . ( 2 ) inventory turns ( annualized ) are calculated as the ratio of four times our cost of sales for the quarter to average inventory . ( 3 ) days inventory on hand is calculated as the ratio of average inventory for the quarter to average daily cost of sales for the quarter . ( 4 ) accounts payable days ( a measure of how quickly we pay our suppliers ) , or `` dpo `` , is calculated as the ratio of 365 days to accounts payable turns , in which accounts payable turns is calculated as the ratio of four times our cost of sales for the quarter to average accounts payable . ( 5 ) cash cycle days is calculated as days inventory on hand plus days sales outstanding minus accounts payable days . story_separator_special_tag board of directors has authorized us to repurchase shares of our common stock , subject to a dollar limitation . the timing of repurchases will depend upon capital needs to support the growth of our business , market conditions and other factors . although stock repurchases are intended to increase stockholder value , purchases of shares reduce our liquidity . we repurchased 5.0 million and 4.3 million shares of our common stock for $ 146 million and $ 160 million in the open market in 2018 and 2017 , respectively . as of september 29 , 2018 , subject to limitations on stock repurchases contained in our debt agreements , $ 108 million remains available under programs authorized by the board of directors , none of which is subject to an expiration date . during 2018 , we entered into a receivables purchase agreement ( the “ rpa ” ) with certain third-party banking institutions for the sale of trade receivables generated from sales to certain customers . a maximum of $ 540 million of sold receivables can be outstanding at any point in time under this program , subject to limitations under our amended cash flow revolver . trade receivables sold pursuant to the rpa are serviced by us . in addition to the rpa , we have the option to participate in trade receivables sales programs that have been implemented by certain of our customers , as in effect from time to time . we do not service trade receivables sold under these other programs . under each of the programs noted above , we sell our entire interest in a trade receivable for 100 % of face value , less a discount

