Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).  Yesx  No☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company, or an emerging growth company.  See the definitions of "large“large accelerated filer"filer”, "accelerated filer"“accelerated filer”, and "smaller“smaller reporting company"company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP) have been condensed or omitted.  Results of operations for the interim periods presented are not necessarily indicative of results which may be expected for any other interim period or for the year as a whole.  This Quarterly Report on Form 10-Q should be read in conjunction with the Company'sCompany’s Annual Report on Form 10-K, including the annual financial statements incorporated therein.

The accompanying unaudited interim financial statements include all normal recurring adjustments which are, in the opinion of management, necessary for a fair presentation of the results for the interim periods includedpresented herein.  The fiscal quarter ended April 1, 2017 contained 13 weeks, while the fiscal quarter ended April 2, 2016 contained 14 weeks, while the fiscal quarter ended March 28, 2015 contained 13 weeks.

Basic per share amounts have been computed based on the average number of common shares outstanding.  Diluted per share amounts reflect the increase in average common shares outstanding that would result from the assumed exercise of outstanding stock options and vesting of restricted stock awards, computed using the treasury stock method.  Approximately 579 thousand and 180 thousand stock-based awards were excluded from the computation of diluted earnings per share for the quartersquarter ended April 2, 2016 and March 28, 2015, respectively, because they were antidilutive.

During the first quarter of 2016, the Company made changes to its management reporting structure as a result of a change in the way the Chief Executive Officer, who serves as the Chief Operating Decision Maker, manages and evaluates the business, makes key operating decisions, and allocates resources.  Previously, the Company had two reportable segments: Plumbing & Refrigeration and OEM.  During the quarter, the Company realigned its operating segments into three reportable segments: Piping Systems, Industrial Metals, and Climate.  Management has recast certain prior period amounts to conform the current period presentation. Each of the Company’s reportable segments is composed of certain operating segments that are aggregated primarily by the nature of products offered as follows:

Piping Systems is composed of the following operating segments: Domestic Piping Systems Group, Canadian Operations, European Operations, Trading Group, and Mueller-Xingrong the Company's(the Company’s Chinese joint venture.venture), and Jungwoo-Mueller (the Company’s South Korean joint venture).  The Domestic Piping Systems Group manufactures copper tube and fittings, plastic fittings, and line sets.  These products are manufactured in the U.S., sold in the U.S, and exported to markets worldwide.   Outside the U.S., the Canadian Operations manufacture copper tube and line sets in Canada and sell the products primarily in the U.S. and Canada, and the European Operations manufacture copper tube in the U.K. which is sold primarily in Europe.  The Trading Group manufactures pipe nipples and imports and resells brass and plastic plumbing valves, malleable iron fittings, faucets, and plumbing specialty products in the U.S. and Mexico.  Mueller-Xingrong manufactures engineered copper tube primarily for air-conditioning applications in China.  Jungwoo-Mueller manufactures copper-based joining products that are sold worldwide.  The Piping System segment'sSystems segment’s products are sold primarily to plumbing, refrigeration, and air-conditioning wholesalers, hardware wholesalers and co-ops, building product retailers, and air-conditioning OEMs.original equipment manufacturers (OEMs).

Industrial Metals is composed of the following operating segments: Brass Rod & Copper Bar Products, Impacts & Micro Gauge, and Brass Value-Added Products.  These businesses manufacture brass rod, impact extrusions, and forgings, as well as a wide variety of end products including plumbing brass, automotive components, valves, fittings, and gas assemblies.  These products are manufactured in the U.S. and sold primarily to OEMs in the U.S,U.S., many of which are in the industrial, construction, heating, ventilation, and air-conditioning, plumbing, and refrigeration markets.

Climate is composed of the following operating segments: Refrigeration Products, Fabricated Tube Products, Westermeyer, and Turbotec.  These domestic businesses manufacture and fabricate valves, assemblies, high pressure components, and assembliescoaxial heat exchangers primarily for the heating, ventilation, air-conditioning, and refrigeration markets in the U.S.

Summarized segment information is as follows:

The Company'sCompany’s earnings and cash flows are subject to fluctuations due to changes in commodity prices, foreign currency exchange rates, and interest rates.  The Company uses derivative instruments such as commodity futures contracts, foreign currency forward contracts, and interest rate swaps to manage these exposures.

All derivatives are recognized in the Condensed Consolidated Balance Sheets at their fair value.  On the date the derivative contract is entered into, it is either a) designated as (i) a hedge of (i) a forecasted transaction or the variability of cash flow to be paid (cash flow hedge), or (ii) a hedge of the fair value of a recognized asset or liability (fair value hedge), or b) not designated in a hedge accounting relationship, even though the derivative contract was executed to mitigate an economic exposure, as the Company does not enter into derivative contracts for trading purposes (economic hedge).  Changes in the fair value of a derivative instrument that is qualified, designated and highly effective as a cash flow hedge are recorded in stockholders’ equity within accumulated other comprehensive income (AOCI), to the extent effective, until they are reclassified to earnings in the same period or periods during which the hedged transaction affects earnings.  Changes in the fair value of a derivative instrument that is qualified, designated and highly effective as a fair value hedge, along with the gain or loss on the hedged recognized asset or liability that is attributable to the hedged risk, are recorded in current earnings.  Changes in the fair value of undesignated derivative instrumentsderivatives executed as economic hedges and the ineffective portion of designated derivative instrumentsderivatives are reported in current earnings.

The Company documents all relationships between hedgingderivative instruments and hedged items, as well as the risk-management objective and strategy for undertaking various hedge transactions.  This process includes linking all derivativesderivative instruments that are designated as fair value hedges to specific assets and liabilities in the Condensed Consolidated Balance Sheets and linking cash flow hedges to specific forecasted transactions or variability of cash flow.

The Company also assesses, both at the hedge'shedge’s inception and on an ongoing basis, whether the designated derivativesderivative instruments that are used in hedging transactions are highly effective in offsetting changes in cash flow or fair values of hedged items.  When a derivative instrument is determined not to be highly effective as a hedge or the underlying hedged transaction is no longer probable of occurring, hedge accounting is discontinued prospectively in accordance with the derecognition criteria for hedge accounting.

Copper and brass represent the largest component of the Company'sCompany’s variable costs of production.  The cost of these materials is subject to global market fluctuations caused by factors beyond the Company'sCompany’s control.  The Company occasionally enters into forward fixed-price arrangements with certain customers; the risk of these arrangements is generally managed with commodity futures contracts.   These futures contracts have been designated as cash flow hedges.  

At April 2, 2016,1, 2017, the Company held open futures contracts to purchase approximately $23.7$20.1 million of copper over the next nine months related to fixed price sales orders.  The fair value of those futures contracts was a $21$178 thousand net gain position, which was determined by obtaining quoted market prices (level 1 within the fair value hierarchy).  In the next twelve12 months, the Company will reclassify into earnings realized gains or losses relating to cash flow hedges.  At April 2, 2016,1, 2017, this amount was approximately $105$92 thousand of deferred net losses,gains, net of tax.

The Company may also enter into futures contracts to protect the value of inventory against market fluctuations.  At April 2, 2016,1, 2017, the Company held open futures contracts to sell approximately $21.0$38.6 million of copper over the next foursix months related to copper inventory.  The fair value of those futures contracts was a $307$293 thousand lossnet gain position, which was determined by obtaining quoted market prices (level 1 within the fair value hierarchy).

On February 20, 2013, the Company entered into a two-year forward-starting interest rate swap agreement with an effective date of January 12, 2015, and an underlying notional amount of $200.0 million, pursuant to which the Company receives variable interest payments based on one-month LIBOR and pays fixed interest at a rate of 1.4 percent.   Based on the Company'sCompany’s current variable premium pricing on its Term Loan Facility,revolving credit facility, the all-in fixed rate as of the effective date is 2.72.46 percent.  The interest rate swap will mature on December 11, 2017, and is structured to offset the interest rate risk associated with the Company'sCompany’s floating-rate, LIBOR-based Term Loan Facility Agreement.   The swap was designated and accounted for as a cash flow hedge fromat inception. During the fourth quarter of 2016, the Company discontinued hedge accounting prospectively.

The fair value of the interest rate swap is estimated based on the present value of the difference between expected cash flows calculated at the contracted interest rate and the expected cash flows at the current market interest rate using observable benchmarks for LIBOR forward rates at the end of the period (level 2 within the fair value hierarchy).  Interest payable and receivable under the swap agreement is accrued and recorded as an adjustment to interest expense.  The fair value of the interest rate swap was a $2.3 million$295 thousand loss position at April 2, 2016,1, 2017, and there was $1.5 million$405 thousand of deferred net losses, net of tax, included in AOCI that are expected to be reclassified into interest expense over the term of the hedged item.interest rate swap.

The Company presents its derivative assets and liabilities in ourthe Condensed Consolidated Balance Sheets on a net basis by counterparty.  The following table summarizes the location and fair value of the derivative instruments and disaggregates ourthe net derivative assets and liabilities into gross components on a contract-by-contract basis:

The following tables summarize amounts recognized in and reclassified from AOCI during the period:

The Company enters into futures and forward contracts that closely match the terms of the underlying transactions.  As a result, the ineffective portion of the open hedge contracts through April 2, 20161, 2017 was not material to the Condensed Consolidated Statements of Income.

The Company primarily enters into International Swaps and Derivatives Association master netting agreements with major financial institutions that permit the net settlement of amounts owed under their respective derivative contracts.  Under these master netting agreements, net settlement generally permits the Company or the counterparty to determine the net amount payable for contracts due on the same date and in the same currency for similar types of derivative transactions.  The master netting agreements generally also provide for net settlement of all outstanding contracts with a counterparty in the case of an event of default or a termination event.  The Company does not offset fair value amounts for derivative instruments and fair value amounts recognized for the right to reclaim cash collateral.  At April 2, 20161, 2017 and December 26, 2015,31, 2016, the Company had recorded restricted cash in other current assets of $2.7$2.0 million and $2.6$1.4 million, respectively, as collateral related to open derivative contracts under the master netting arrangements.

The Company records its proportionate share of the investee'sinvestees’ net income or loss one quarter in arrears as income (loss) from unconsolidated affiliates, net of tax, in the Condensed Consolidated Statements of Income and its proportionate share of the investees’ other comprehensive income (loss), net of income taxes, in the Condensed Consolidated Statements of Comprehensive Income. In general, the equity investment in unconsolidated affiliates is equal to the current equity investment plus the entities’ undistributed earnings. 

The following tables present summarized financial information derived from the Company'sCompany’s equity method investees'investees’  combined consolidated financial statements, which are prepared in accordance with U.S. GAAP.