|         |                                                    |
|---------|----------------------------------------------------|
| • | Fiscal second quarter 2016 revenue of $619 million |

|         |                                                                                                              |
|---------|--------------------------------------------------------------------------------------------------------------|
| • | GAAP diluted EPS of $0.50, non-GAAP diluted EPS of $0.55, excluding $0.05 per share of restructuring charges |

|         |                                                                                                                                                                       |
|---------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| • | Initiates fiscal third quarter 2016 revenue guidance of $640 - $670 million with non-GAAP diluted EPS of $0.73 to $0.81, excluding any restructuring or other charges |

|                                   |
|-----------------------------------|
|                                   |  |  |  |  |  |  |  |  |
|                              |   | Three Months Ended |
|                              |   | Apr 2, 2016 |   | Apr 2, 2016 |   | Jul 2, 2016 |
|                              |   | Q2F16 Results |   | Q2F16 Guidance |   | Q3F16 Guidance |
| Summary GAAP Items                |   |   |   |   |   |
| Revenue (in millions)             |  | $619 |  |   | $600 to $630 |   | $640 to $670 |
| Operating margin                  | 3.8 | % |   |   |   |   |
| Diluted EPS                       |  | $0.50 |  |   |   |   |   |
|                              |   |   |   |   |   |   |
| Summary Non-GAAP Items (1)        |   |   |   |   |   |
| Non-GAAP operating margin (2)     | 4.1 | % |   | 3.6% to 4.0% |   | 4.7% to 5.0% |
| Non-GAAP diluted EPS (2)(3)       |  | $0.55 |  |   | $0.47 to $0.55 |   | $0.73 to $0.81 |
| Return on invested capital (ROIC) | 11.6 | % |   |   |   |   |
| Economic Return                   | 0.6 | % |   |   |   |   |
|                              |   |   |   |   |   |   |
| (1)                               | Refer to Non-GAAP Supplemental Information Tables 1 and 2 for a reconciliation to GAAP measures. |
| (2)                               | Excludes restructuring charges of $1.9 million for the three months ended April 2, 2016. |
| (3)                               | Includes stock-based compensation expense of $0.11 for Q2F16 results and $0.11 for Q3F16 guidance. |

|         |                                                                                                                                    |
|---------|------------------------------------------------------------------------------------------------------------------------------------|
| • | Won 38 programs during the quarter representing approximately $174 million in annualized revenue when fully ramped into production |

|         |                                                                                   |
|---------|-----------------------------------------------------------------------------------|
| • | Trailing four quarter wins total approximately $667 million in annualized revenue |

|         |                                                                              |
|---------|------------------------------------------------------------------------------|
| • | Purchased $7.3 million of our shares at an average price of $34.88 per share |

----

|                                                                                                  |
|--------------------------------------------------------------------------------------------------|
|                                                                                                  |  |  |  |  |  |  |  |  |  |  |  |
| Quarterly Comparison                                                                             | Three Months Ended |
|                                                                                             | Apr 2, 2016 |   | Jan 2, 2016 |   | Apr 4, 2015 |
| (in thousands, except EPS)                                                                       | Q2F16 |   | Q1F16 |   | Q2F15 |
| Revenue                                                                                          |  | $618,660 |  |   |  | $616,664 |  |   |  | $651,285 |  |
| Gross profit                                                                                     |  | $53,272 |  |   |  | $50,059 |  |   |  | $59,777 |  |
| Operating profit                                                                                 |  | $23,346 |  |   |  | $21,524 |  |   |  | $29,452 |  |
| Net income                                                                                       |  | $16,787 |  |   |  | $14,448 |  |   |  | $23,594 |  |
| Diluted EPS                                                                                      |  | $0.50 |  |   |  | $0.42 |  |   |  | $0.69 |  |
| Adjusted net income*                                                                             |  | $18,704 |  |   |  | $15,955 |  |   |  | $23,594 |  |
| Non-GAAP diluted EPS*                                                                            |  | $0.55 |  |   |  | $0.47 |  |   |  | $0.69 |  |
|                                                                                             |   |   |   |   |   |
| Gross margin                                                                                     | 8.6 | % |   | 8.1 |  % |   | 9.2 | % |
| Operating margin                                                                                 | 3.8 | % |   | 3.5 |  % |   | 4.5 | % |
| Adjusted operating margin*                                                                       | 4.1 | % |   | 3.7 |  % |   | 4.5 | % |
|                                                                                             |   |   |   |   |   |
| ROIC*                                                                                            | 11.6 | % |   | 10.8 |  % |   | 14.5 | % |
| Economic Return*                                                                                 | 0.6 | % |   | -0.2 |  % |   | 3.5 | % |
|                                                                                             |   |   |   |   |   |
| *Refer to Non-GAAP Supplemental Information Tables 1 and 2 for a reconciliation to GAAP measures |

|                               |
|-------------------------------|
|                               |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Market Sector ($ in millions) | Three Months Ended |
|                          | Apr 2, 2016 Q2F16 |   | Jan 2, 2016 Q1F16 |   | Apr 4, 2015 Q2F15 |
| Networking/Communications     | $ | 157 |  | 25 | % |   | $ | 157 |  | 25 | % |   | $ | 210 |  | 32 | % |
| Healthcare/Life Sciences      | 190 |  | 31 | % |   | 191 |  | 31 | % |   | 191 |  | 29 | % |
| Industrial/Commercial         | 169 |  | 27 | % |   | 173 |  | 28 | % |   | 160 |  | 25 | % |
| Defense/Security/Aerospace    | 103 |  | 17 | % |   | 96 |  | 16 | % |   | 90 |  | 14 | % |
| Total Revenue                 | $ | 619 |  |   |   | $ | 617 |  |   |   | $ | 651 |  |   |

----

|                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                                                    |  |  |  |  |  |
| Cash Conversion Cycle                                                                                                                              | Three Months Ended |
|                                                                                                                                               | Apr 2, 2016 Q2F16 |   | Jan 2, 2016 Q1F16 |   | Apr 4, 2015 Q2F15 |
| Days in Accounts Receivable                                                                                                                        | 48 |   | 53 |   | 48 |
| Days in Inventory                                                                                                                                  | 91 |   | 88 |   | 86 |
| Days in Accounts Payable                                                                                                                           | (62) |   | (59) |   | (63) |
| Days in Cash Deposits                                                                                                                              | (11) |   | (11) |   | (12) |
| Annualized Cash Cycle*                                                                                                                             | 66 |   | 71 |   | 59 |
| *We calculate cash cycle as the sum of days in accounts receivable and days in inventory, less days in accounts payable and days in cash deposits. |

|                                |
|--------------------------------|
|                                |  |
| What:           | Plexus Fiscal Second Quarter 2016 Earnings Conference Call and Webcast |
| When:           | Thursday, April 21, 2016 at 8:30 a.m. Eastern Time |
| Where:     | Participants are encouraged to join the live webcast at the investor relations section of the Plexus website, www.plexus.com or directly at: http://edge.media-server.com/m/p/287yxk62   Conference call at +1.888.771.4371 with passcode: 42104018 |
| Replay:         | The webcast will be archived on the Plexus website and available via telephone replay at +1.888.843.7419 or +1.630.652.3042 with passcode: 42104018 |

----

----

|                                                 |
|-------------------------------------------------|
|                                                 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| PLEXUS                                          |
| CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS |
| (in thousands, except per share data)           |
| (unaudited)                                     |
|                                            |   |   |   |   |   |
|                                            | Three Months Ended |   | Six Months Ended |
|                                            | Apr 2, |   | Apr 4, |   | Apr 2, |   | Apr 4, |
|                                            | 2016 |   | 2015 |   | 2016 |   | 2015 |
| Net sales                                       |  | $618,660 |  |   |  | $651,285 |  |   |  | $1,235,324 |  |   |  | $1,315,975 |  |
| Cost of sales                                   | 565,388 |  |   | 591,508 |  |   | 1,131,993 |  |   | 1,194,784 |  |
| Gross profit                                    | 53,272 |  |   | 59,777 |  |   | 103,331 |  |   | 121,191 |  |
| Selling and administrative expenses             | 28,009 |  |   | 30,325 |  |   | 55,037 |  |   | 61,266 |  |
| Restructuring charges                           | 1,917 |  |   | — |  |   | 3,424 |  |   | 1,691 |  |
| Operating income                                | 23,346 |  |   | 29,452 |  |   | 44,870 |  |   | 58,234 |  |
| Other income (expense):                         |   |   |   |   |   |   |   |
| Interest expense                                | (3,674) |  |   | (3,383) |  |   | (7,208) |  |   | (7,160) |  |
| Interest income                                 | 1,015 |  |   | 788 |  |   | 1,947 |  |   | 1,686 |  |
| Miscellaneous                                   | (1,128) |  |   | (60) |  |   | (2,748) |  |   | 78 |  |
| Income before income taxes                      | 19,559 |  |   | 26,797 |  |   | 36,861 |  |   | 52,838 |  |
| Income tax expense                              | 2,772 |  |   | 3,203 |  |   | 5,626 |  |   | 6,165 |  |
| Net income                                      |  | $16,787 |  |   |  | $23,594 |  |   |  | $31,235 |  |   |  | $46,673 |  |
| Earnings per share:                             |   |   |   |   |   |   |   |
| Basic                                           |  | $0.50 |  |   |  | $0.70 |  |   |  | $0.94 |  |   |  | $1.39 |  |
| Diluted                                         |  | $0.50 |  |   |  | $0.69 |  |   |  | $0.92 |  |   |  | $1.36 |  |
| Weighted average shares outstanding:            |   |   |   |   |   |   |   |
| Basic                                           | 33,319 |  |   | 33,606 |  |   | 33,368 |  |   | 33,604 |  |
| Diluted                                         | 33,834 |  |   | 34,342 |  |   | 33,957 |  |   | 34,391 |  |

----

|                                           |
|-------------------------------------------|
|                                           |  |  |  |  |  |  |  |  |  |  |  |
| PLEXUS                                    |
| NON-GAAP SUPPLEMENTAL INFORMATION TABLE 1 |
| (in thousands, except per share data)     |
| (unaudited)                               |
|                                      |   |   |   |   |   |
|                                      | Three Months Ended |
|                                      | Apr 2, |   | Jan 2, |   | Apr 4, |
|                                      | 2016 |   | 2016 |   | 2015 |
| Operating profit, as reported             | $ | 23,346 |  |   | $ | 21,524 |  |   | $ | 29,452 |  |
| Operating margin, as reported             | 3.8 | % |   | 3.5 | % |   | 4.5 | % |
|                                      |   |   |   |   |   |
| Non-GAAP adjustments:                     |   |   |   |   |   |
| Restructuring costs*                      | 1,917 |  |   | 1,507 |  |   | — |  |
|                                      |   |   |   |   |   |
| Operating profit, as adjusted             | $ | 25,263 |  |   | $ | 23,031 |  |   | $ | 29,452 |  |
| Operating margin, as adjusted             | 4.1 | % |   | 3.7 | % |   | 4.5 | % |
|                                      |   |   |   |   |   |
| Net income, as reported                   | $ | 16,787 |  |   | $ | 14,448 |  |   | $ | 23,594 |  |
|                                      |   |   |   |   |   |
| Non-GAAP adjustments:                     |   |   |   |   |   |
| Restructuring costs*                      | 1,917 |  |   | 1,507 |  |   | — |  |
|                                      |   |   |   |   |   |
| Net income, as adjusted                   | $ | 18,704 |  |   | $ | 15,955 |  |   | $ | 23,594 |  |
|                                      |   |   |   |   |   |
| Diluted earnings per share, as reported   | $ | 0.50 |  |   | $ | 0.42 |  |   | $ | 0.69 |  |
|                                      |   |   |   |   |   |
| Non-GAAP adjustments:                     |   |   |   |   |   |
| Restructuring costs                       | 0.05 |  |   | 0.05 |  |   | — |  |
|                                      |   |   |   |   |   |
| Diluted earnings per share, as adjusted   | $ | 0.55 |  |   | $ | 0.47 |  |   | $ | 0.69 |  |
|                                      |   |   |   |   |   |
| *Summary of restructuring costs           |   |   |   |   |   |
| Employee termination and severance costs  | $ | 1,656 |  |   | $ | 1,394 |  |   | $ | — |  |
| Other exit costs                          | 261 |  |   | 113 |  |   | — |  |
| Total restructuring costs                 | $ | 1,917 |  |   | $ | 1,507 |  |   | $ | — |  |
|                                      |   |   |   |   |   |

----

|                                           |
|-------------------------------------------|
|                                           |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| PLEXUS                                    |
| NON-GAAP SUPPLEMENTAL INFORMATION Table 2 |
|  (in thousands)                      |
| (unaudited)                               |
|                                      |   |   |   |   |   |
| ROIC and Economic Return Calculations     | Six Months Ended |   | Three Months Ended |   | Six Months Ended |
|                                      | Apr 2, |   | Jan 2, |   | Apr 4, |
|                                      | 2016 |   | 2016 |   | 2015 |
| Operating profit                          |   | $ | 44,870 |  |   |   | $ | 21,524 |  |   |   | $ | 58,234 |  |
| Restructuring charges                     |   | 3,424 |  |   |   | 1,507 |  |   |   | 1,691 |  |
| Adjusted operating profit                 |   | $ | 48,294 |  |   |   | $ | 23,031 |  |   |   | $ | 59,925 |  |
|                                      | x | 2 |  |   | x | 4 |  |   | x | 2 |  |
|                                      |   |   |   |   |   |   |   |   |
|                                      |   |   |   |   |   |   |   |   |
| Annualized operating profit               |   | $ | 96,588 |  |   |   | $ | 92,124 |  |   |   | $ | 119,850 |  |
| Tax rate                                  | x | 11 | % |   | x | 12 |  % |   | x | 10 | % |
| Tax impact                                |   | 10,625 |  |   |   | 11,055 |  |   |   | 11,985 |  |
| Operating profit (tax effected)           |   | $ | 85,963 |  |   |   | $ | 81,069 |  |   |   | $ | 107,865 |  |
|                                      |   |   |   |   |   |   |   |   |
| Average invested capital                  | ÷ | $ | 743,112 |  |   | ÷ | $ | 753,078 |  |   | ÷ | $ | 745,441 |  |
|                                      |   |   |   |   |   |   |   |   |
| ROIC                                      |   | 11.6 | % |   |   | 10.8 |  % |   |   | 14.5 | % |
| Weighted average cost of capital          |   | 11.0 | % |   |   | 11.0 |  % |   |   | 11.0 | % |
| Economic return                           |   | 0.6 | % |   |   | -0.2 |  % |   |   | 3.5 | % |

|                           |
|---------------------------|
|                           |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
|                      | Three Months Ended |
| Average Invested Capital  | Apr 2, |   | Jan 2, |   | Oct 3, |   | Jul 4, |   | Apr 4, |   | Jan 3, |   | Sep 27, |
| Calculations              | 2016 |   | 2016 |   | 2015 |   | 2015 |   | 2015 |   | 2015 |   | 2014 |
| Equity                    |  | $871,111 |  |   |  | $850,794 |  |   |  | $842,272 |  |   |  | $835,063 |  |   |  | $808,468 |  |   |  | $792,298 |  |   |  | $781,133 |  |
| Plus:                     |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Debt - current            | 2,300 |  |   | 2,864 |  |   | 3,513 |  |   | 4,281 |  |   | 4,774 |  |   | 4,793 |  |   | 4,368 |  |
| Debt – non-current  | 259,565 |  |   | 259,289 |  |   | 259,257 |  |   | 259,284 |  |   | 260,025 |  |   | 260,990 |  |   | 262,046 |  |
| Less:                     |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Cash and cash equivalents | (409,796) |  |   | (354,728) |  |   | (357,106) |  |   | (354,830) |  |   | (356,296) |  |   | (239,685) |  |   | (346,591) |  |
|                      |  | $723,180 |  |   |  | $758,219 |  |   |  | $747,936 |  |   |  | $743,798 |  |   |  | $716,971 |  |   |  | $818,396 |  |   |  | $700,956 |  |

----

|                                                                         |
|-------------------------------------------------------------------------|
|                                                                         |  |  |  |
| PLEXUS                                                                  |
| CONDENSED CONSOLIDATED BALANCE SHEETS                                   |
| (in thousands, except per share data)                                   |
| (unaudited)                                                             |
|                                                                    |   |   |   |
|                                                                    | Apr 2, |   | Oct 3, |
|                                                                    | 2016 |   | 2015 |
| ASSETS                                                                  |   |   |   |
| Current assets:                                                         |   |   |   |
| Cash and cash equivalents                                               | $409,796 |   | $357,106 |
| Accounts receivable                                                     | 325,392 |   | 384,680 |
| Inventories                                                             | 563,291 |   | 569,371 |
| Deferred income taxes                                                   | 10,522 |   | 10,686 |
| Prepaid expenses and other                                              | 27,095 |   | 22,882 |
| Total current assets                                                    | 1,336,096 |   | 1,344,725 |
| Property, plant and equipment, net                                      | 307,227 |   | 317,351 |
| Deferred income taxes                                                   | 3,591 |   | 3,635 |
| Other                                                                   | 36,610 |   | 36,677 |
| Total non-current assets                                                | 347,428 |   | 357,663 |
| Total assets                                                            | $1,683,524 |   | $1,702,388 |
|                                                                    |   |   |   |
| LIABILITIES AND SHAREHOLDERS’ EQUITY                              |   |   |   |
| Current liabilities:                                                    |   |   |   |
| Current portion of long-term debt and capital lease obligations         | $2,300 |   | $3,513 |
| Accounts payable                                                        | 383,092 |   | 400,710 |
| Customer deposits                                                       | 70,620 |   | 81,359 |
| Accrued salaries and wages                                              | 31,252 |   | 49,270 |
| Other accrued liabilities                                               | 41,890 |   | 44,446 |
| Total current liabilities                                               | 529,154 |   | 579,298 |
| Long-term debt and capital lease obligations, net of current portion    | 259,565 |   | 259,257 |
| Deferred income taxes                                                   | 9,664 |   | 9,664 |
| Other liabilities                                                       | 14,030 |   | 11,897 |
| Total non-current liabilities                                           | 283,259 |   | 280,818 |
| Total liabilities                                                       | 812,413 |   | 860,116 |
| Shareholders’ equity:                                             |   |   |   |
| Common stock, $.01 par value, 200,000 shares authorized,                |   |   |   |
| 50,757 and 50,554 shares issued, respectively,                          |   |   |   |
| and 33,267 and 33,500 shares outstanding, respectively                  | 508 |   | 506 |
| Additional paid-in-capital                                              | 502,625 |   | 497,488 |
| Common stock held in treasury, at cost, 17,490 and 17,054, respectively | (525,706) |   | (509,968) |
| Retained earnings                                                       | 891,952 |   | 860,717 |
| Accumulated other comprehensive income (loss)                           | 1,732 |   | (6,471) |
| Total shareholders’ equity                                        | 871,111 |   | 842,272 |
| Total liabilities and shareholders’ equity                        | $1,683,524 |   | $1,702,388 |

----

|                                           |
|-------------------------------------------|
|                                           |  |  |  |  |  |
| PLEXUS                                    |
| REVENUE BY REPORTABLE GEOGRAPHIC SEGMENTS |
| (in thousands)                            |
| (unaudited)                               |
|                                      |   |   |   |   |   |
|                                      | Three Months Ended |
|                                      | Apr 2, |   | Jan 2, |   | Apr 4, |
|                                      | 2016 |   | 2016 |   | 2015 |
| Americas                                  | $330,240 |   | $305,097 |   | $328,753 |
| Asia-Pacific                              | 270,544 |   | 299,346 |   | 319,156 |
| Europe, Middle East, and Africa           | 43,703 |   | 42,087 |   | 35,773 |
| Elimination of inter-segment sales        | (25,827) |   | (29,866) |   | (32,397) |
| Total Revenue                             | $618,660 |   | $616,664 |   | $651,285 |