Willis Electric Co., Ltd. v. Polygroup Limited

U.S. District Court, District of Minnesota

Willis Electric Co., Ltd. v. Polygroup Limited

Trial Court Opinion

                 UNITED STATES DISTRICT COURT                            
                    DISTRICT OF MINNESOTA                                


Willis Electric Co., Ltd.,              Case No. 15-cv-3443 (JNE/DTS)    

                   Plaintiff,                                            

ORDER

     v.                                                                  

Polygroup Limited et al,                                                 

                   Defendants.                                           


    This matter is before the Court on the issue of enhanced damages and Plaintiff Willis 
Electric Co., Ltd.’s (“Willis Electric”) motion for prejudgment and post-judgment interest, 
(Dkt. 965).  Following the jury verdict, the Court requested supplemental briefing on the 
issue of whether enhanced damages should be awarded based on the willful infringement 
finding.  (Dkt. 952.)   Defendants Polygroup Limited (Macao Commercial Offshore), 
Polygroup Macau Limited (BVI), Polytree (H.K.) Co. Ltd., Polygroup Trading Limited 
(collectively, “Defendants”) submitted briefing in opposition to enhanced damages and in 
opposition to the motion for prejudgment and post-judgment interest.  For the reasons 
addressed below, the Court declines to enhance the jury award and grants the motion for 
prejudgment and post-judgment interest.                                   
                         BACKGROUND                                      
    Willis Electric filed this patent infringement action in 2015 alleging that Polygroup 
infringed various claims of several patents, including 
U.S. Patent No. 8,454,186
 (’186 
patent).  Polygroup asserted defenses of non-infringement and invalidity of these patents.  
After motion practice and inter partes review (IPR) proceedings challenging the validity of 
the asserted patents, see, e.g., Polygroup Ltd. MCO v. Willis Elec. Co., Ltd., 2021-1401, 

2021-1402, 
2022 WL 1183332
 (Fed. Cir. Apr. 20, 2022), the sole claim tried to the jury 
was claim 15 of the ’186 patent.                                          
    The jury trial commenced on January 8, 2024, before this Court.  On January 17, 
2024, the jury returned a unanimous verdict finding that Polygroup willfully infringed 
claim 15 of the ’186 patent.  The jury awarded $42,494,772 in damages.  Following the 
jury verdict, the Court requested supplemental briefing on the issue of whether enhanced 

damages should be awarded based on the willful infringement finding.  Also following the 
jury verdict, Willis Electric filed a motion for prejudgment and post-judgment interest.   
                           ANALYSIS                                      
I.   Willful Infringement and Enhanced Damages                            
    A.   Legal Standard                                                  

    The Court “may increase the damages up to three times the amount found or 
assessed.”    
35 U.S.C. § 284
.    Enhanced  damages  are  “designed  as  a  ‘punitive’  or 
‘vindictive’ sanction for egregious infringement behavior.”  Halo Elecs., Inc. v. Pulse 
Elecs., Inc., 
136 S. Ct. 1923, 1932
, 
195 L. Ed. 2d 278
 (2016).  “The sort of conduct 
warranting  enhanced  damages  has  been  variously  described  .  .  .  as  willful,  wanton, 

malicious,  bad-faith,  deliberate,  consciously  wrongful,  flagrant,  or  —  indeed  — 
characteristic of a pirate.”  
Id.
  Importantly, “[e]nhanced damages are generally only 
appropriate in egregious cases of misconduct.”  Presidio Components, Inc. v. Am. Tech. 
Ceramics Corp., 
875 F.3d 1369, 1382
 (Fed. Cir. 2017).                     
    The decision to award enhanced damages is committed to the court’s discretion.  
Halo Elecs., 
136 S. Ct. at 1934-35
.  In deciding whether to award enhanced damages, the 

court  considers  “the  particular  circumstances  of  the  case  to  determine  whether  it  is 
egregious.”  Presidio Components, 
875 F.3d at 1383
.  Even in cases where the jury finds 
willful infringement, a court is not required to award enhanced damages.  
Id. at 1382
. 
    Courts  traditionally  examine  the  Read  factors  in  deciding  whether  to  award 
enhanced damages: (1) whether the infringer deliberately copied the ideas or design of 
another;  (2)  whether  the  infringer,  when  he  knew  of  the  other’s  patent  protection, 

investigated the scope of the patent and formed a good-faith belief that it was invalid or 
that it was not infringed; (3) the infringer’s behavior as a party to the litigation; (4) 
defendant’s  size  and  financial  condition;  (5)  closeness  of  the  case;  (6)  duration  of 
defendant’s misconduct; (7) remedial action by the defendant; (8) defendant’s motivation 
for harm; and (9) whether defendant attempted to conceal its misconduct.  Read Corp. v. 

Portec, Inc., 
970 F.2d 816, 827
 (Fed. Cir. 1992).  The Read factors are “non-exclusive,” 
but provide a structure to the Court’s analysis.  Georgetown Rail Equip. Co. v. Holland 
L.P., 
867 F.3d 1229
, 1244-45 & n.6 (Fed. Cir. 2017).                      
    Several of the Read factors relate to issues “that were not before the jury and/or 
which the jury would not have been in a position to assess.”  Idenix Pharms. LLC v. Gilead 

Scis., Inc., 
271 F. Supp. 3d 694, 697
 (D. Del. 2017).  “Therefore, it is entirely appropriate, 
even required, for the Court to consider — based on its extensive familiarity with the entire 
course of this case, as well as what it observed a trial — where, notwithstanding the jury’s 
verdict  in  favor  of  [Willis  Electric],  substantial  contrary  evidence  was  presented  by 
[Polygroup].”  
Id.
  Indeed, the Court cannot substitute its factual determination for a jury’s 
willfulness finding.  Advanced Cardiovascular Sys., Inc. v. Medtronic, Inc., 
265 F.3d 1294, 1311
 (Fed. Cir. 2001).  However, this does not prevent the Court from “observing where, 
as the case may be, there was also substantial evidence presented by the willful infringer, 
where the jury may have made findings that were not supported by the record, and where 
the jury heard no evidence and cannot be presumed to have made a particular finding.”  
Idenix Pharms., 
271 F. Supp. 3d at 697
.                                   

    B.   Analysis                                                        
    The Court finds that, based on the totality of the circumstances, Polygroup did not 
engage in the type of egregious  misconduct warranting  enhanced damages under  
35 U.S.C. § 284
 and Halo.  Enhanced damages are generally appropriate only in “egregious 
cases of misconduct beyond typical infringement.”  Halo, 
136 S. Ct. at 1935
; see also 

Presidio Components, 
875 F.3d at 1382
.                                    
    Willis Electric argues several factors from the Read Corp. test support increasing 
damages, including evidence suggesting Polygroup may have deliberately copied Willis 
Electric’s patented “One Plug” artificial tree design, failed to form a good faith belief of 
non-infringement or invalidity, engaged in concerning litigation conduct, has substantial 

financial resources as the world’s largest artificial tree company, and did not attempt to 
switch to a non-infringing alternative until 2019.  
970 F.2d at 827
.  Willis Electric also 
cites the lengthy six-year infringement period and Polygroup’s rule against writing emails 
about intellectual property (IP) issues.                                  
    However, Polygroup counters that it independently developed its initial “Quick Set” 
tree designs before seeing the One Plug tree, and that its engineers reasonably believed the 

Quick Set trees did not infringe and the patent was invalid over prior art such as the Loomis 
patent.  Polygroup points to its pursuit of IPR challenges as evidence of its good faith 
invalidity position.  Polygroup further argues that both parties litigated aggressively, that 
artificial trees are a minor product line, and that it lacked egregious motivations or clear 
concealment of evidence warranting enhanced damages.                      
    The Court finds that Willis Electric’s copying evidence, while concerning, does not 

definitively show egregious infringement.  At most, the evidence indicates a company 
monitoring a competitor’s anticipated patent and aggressively developing a competing 
product, not “wanton and malicious pirac[y].”  Halo, 
136 S. Ct. at 1932
 (quoting Seymour 
v. McCormick, 
57 U.S. 480, 488
, 
14 L. Ed. 1024
 (1853)).  The Court credits Polygroup’s 
engineers’ good faith belief in non-infringement and invalidity based on their analysis and 

IPR petitions.  See Presidio Components, 
875 F.3d at 1382-83
 (noting courts need only 
“consider the particular circumstances of the case to determine whether it is egregious”).  
Willis  Electric’s  litigation  misconduct  assertions  do  not  clearly  show  extraordinary 
malfeasance.  See Halo, 
136 S. Ct. at 1932, 1934
.  And while the infringement duration 
was substantial, Polygroup’s preemptive redesign efforts in 2019 mitigate against deeming 

this an egregious case.  See Read Corp., 
970 F.2d at 827
.                 
    In sum, considering the totality of the circumstances, Polygroup’s conduct does not 
constitute  the  type  of  willful,  wanton,  malicious,  bad-faith,  deliberate,  consciously 
wrongful, flagrant, or “characteristic of a pirate” behavior required for enhanced damages 
under Section 284 and Halo.  
136 S. Ct. at 1932
.  The evidence fails to show the sort of 
egregious  infringement  behavior  or  “misconduct  beyond  typical  infringement” 

contemplated in Halo that would mandate increasing the award here.  
Id. at 1935
; see also 
Presidio Components, 
875 F.3d at 1382
.  Accordingly, enhanced damages are denied. 
II.  Prejudgment Interest                                                 
    “[P]rejudgment interest should ordinarily be awarded under [35 U.S.C.] § 284.”  
Gen. Motors Corp. v. Devex Corp., 
461 U.S. 648, 656
, 
103 S. Ct. 2058, 2063
 (1983).  “In 
the typical case an award of prejudgment interest is necessary to ensure that the patent 

owner is placed in as good a position as he would have been in had the infringer entered 
into a reasonable royalty agreement.”  
Id. at 655
.  The Court has “wide latitude in the 
selection of interest rates.”  Uniroyal, Inc. v. Rudkin-Wiley Corp., 
939 F.2d 1540, 1545
 
(Fed. Cir. 1991).  Section 284 does not specify the interest rate to be used, and “[a] variety 
of rates have been utilized by courts in patent cases, including statutory rates set by state 

statutes, the U.S. Treasury bill rate, the prime rate, the prime rate plus a percentage, and a 
rate on borrowed funds.”  Global Traffic Techs., LLC v. Emtrac Sys., Inc., 
2014 U.S. Dist. LEXIS 57840
, 
2014 WL 1663420
, at *15 (D. Minn. Apr. 25, 2014), aff’d in part, rev’d in 
part on different grounds, 
620 F. App’x 895
 (Fed. Cir. 2015).  “[C]ourts often use the 
statutory interest rate of the state in which they sit.”  
2014 U.S. Dist. LEXIS 57840
, [WL] 

at *16.  Prejudgment interest is awarded from the date of infringement to the date of 
judgment.  Nickson Indus., Inc. v. Rol Mfg. Co., 
847 F.2d 795, 800
 (Fed. Cir. 1988). 
    First,  the  Court  must  decide  what  interest  rate  should  be  used  in  calculating 
prejudgment interest.  Willis Electric requests that the Court award prejudgment interest of 
10% pursuant to 
Minn. Stat. § 549.09
.  Polygroup argues that 
Minn. Stat. § 334.01
, 
providing a maximum interest rate of 6%, is the appropriate rate to apply.  Applying a rate 

of 6% results in interest amounts ranging between $1-4 million, depending on whether the 
Court applies simple or compounding interest.                             
    Polygroup does not dispute that courts in the District of Minnesota have generally 
awarded interest at the 10% Minnesota statutory rate in patent cases over the last decade.  
However,  Polygroup  argues  that  
Minn. Stat. § 334.01
  should  govern  here  since 
prejudgment interest was otherwise allowed under federal patent law before 
Minn. Stat. § 549.09
 was enacted.  Willis Electric counters that 
Minn. Stat. § 334.01
 does not apply 
because damages were not readily ascertainable until determined by the jury at trial.  
    Second,  the  Court  must  consider  whether  any  circumstances  warrant  limiting 
prejudgment interest.  Polygroup argues that such interest should be denied or reduced 
given Willis Electric’s pursuit of frivolous claims and the excessive jury award.  Willis 

Electric contends that Polygroup fails to prove the required undue delay or prejudice for 
limiting interest.                                                        
    Considering  the  parties’  arguments  and  precedent  in  this  District  regarding 
prejudgment interest in patent cases, the Court finds that the 10% Minnesota statutory rate 
is most appropriate to apply here.  Schwendimann v. Arkwright Advanced Coating, Inc., 

No. 11-820, 
2018 U.S. Dist. LEXIS 127732
, 
2018 WL 3621206
, *22-23 (D. Minn. July 
30, 2018); August Tech. Corp. v. Camtek, Ltd., No. 05-1396, 
2015 U.S. Dist. LEXIS 15017
, 
2015 WL 520546
, at *8 (D. Minn. Feb. 9, 2015).  Courts routinely award interest at the 
Minn. Stat. § 549.09
 rate in patent infringement cases, and Polygroup has not presented 
sufficiently compelling reasons to depart from this standard practice.    

    While Polygroup cites 
Minn. Stat. § 334.01
 and argues damages were ascertainable, 
the record indicates significant disputes existed between the parties’ damages experts 
regarding applicable theories, comparable licenses, and reasonable royalty rates.  This 
supports that damages were not readily ascertainable until determined by the jury verdict.  
Therefore, 
Minn. Stat. § 549.09
 and its 10% rate governs.                 
    In addition, Polygroup fails to prove the undue delay or prejudice needed to limit 

prejudgment interest.  The record instead reflects reasonable diligence by Willis Electric 
in pursuing and prosecuting its infringement claims.  Much of the “delay” Polygroup 
complains  of  was  either  necessitated  by  court  schedules  or  resulted  directly  from 
Polygroup’s own IPR challenges.  Polygroup offers no concrete evidence of corresponding 
prejudice tied to these case events.                                      

    As such, the Court concludes that Willis Electric is entitled to prejudgment interest 
at the 10% Minnesota statutory rate based on the $42,494,772 reasonable royalty damages 
awarded by the jury.  Accrued interest shall be calculated from June 4, 2013 through the 
date of final judgment.                                                   
III.  Post-Judgment Interest                                              

    The Court must decide how much post-judgment interest to award Willis Electric.  
Under 
28 U.S.C. § 1961
(a), “[i]nterest shall be allowed on any money judgment in a civil 
case recovered in a district court.”  “Such interest shall be calculated from the date of the 
entry of judgment, at a rate equal to the weekly average 1-year constant maturity Treasury 
yield . . . for the calendar week preceding the date of judgment.”  
28 U.S.C. § 1961
(a).  
Post-judgment interest applies to both the amount awarded in damages and prejudgment 

interest.  See Travelers Prop. Cas. Ins. Co. of Am. v. Nat’l Union Ins. Co., 
735 F.3d 993, 1008
 (8th Cir. 2013) (citing Arthur Young & Co. v. Reves, 
937 F.2d 1310, 1338
 (8th Cir. 
1991)).                                                                   
    In its motion, Willis Electric requested post-judgment interest at the rate of 4.8%, 
based on the Treasury yield for the week prior to its filing on January 31, 2024.  The 
judgment in this case has not yet been entered.  Thus, consistent with Section 1961(a), the 

appropriate post-judgment interest rate will be the weekly average 1-year Treasury yield 
for the week preceding the Court’s entry of judgment.                     
    The Court grants Willis Electric’s motion for post-judgment interest at the weekly 
average Treasury yield rate, to be calculated from the date judgment is entered until 
satisfaction.  This post-judgment interest shall apply to the total judgment amount, 

including prejudgment interest, and any fee and cost awards.              

ORDER

    Based on the foregoing analysis and all the files, records and proceedings herein, IT 

IS HEREBY ORDERED that:                                                   
    1.   Plaintiff  Willis  Electric’s  reasonable  royalty  damages  of  $42,494,772 
awarded by the jury shall not be enhanced.                                
    2.   Plaintiff  Willis  Electric’s  Motion  for  Prejudgment  and  Post-Judgment 
Interest, (Dkt. 965), is GRANTED.                                         
         a.   The Court’s judgment order, to be entered following this order, shall 

     include the order that Willis Electric is awarded $42,494,772 in reasonable royalty 
     damages, plus prejudgment interest calculated at the 10% Minnesota statutory rate 
     from June 4, 2013 through the date of final judgment.               
         b.   The Court’s judgment order, to be entered following this order, shall 
    also include the order that Willis Electric is entitled to post-judgment interest at the 

    weekly average 1-year Treasury rate, accruing from the date of entry of judgment 
    until the judgment is satisfied.                                     

Dated:  March 8, 2024                   s/Joan N. Ericksen                                             
                                       Joan N. Ericksen                  
                                       United States District Judge      

Trial Court Opinion

                 UNITED STATES DISTRICT COURT                            
                    DISTRICT OF MINNESOTA                                


Willis Electric Co., Ltd.,              Case No. 15-cv-3443 (JNE/DTS)    

                   Plaintiff,                                            

ORDER

     v.                                                                  

Polygroup Limited et al,                                                 

                   Defendants.                                           


    This matter is before the Court on the issue of enhanced damages and Plaintiff Willis 
Electric Co., Ltd.’s (“Willis Electric”) motion for prejudgment and post-judgment interest, 
(Dkt. 965).  Following the jury verdict, the Court requested supplemental briefing on the 
issue of whether enhanced damages should be awarded based on the willful infringement 
finding.  (Dkt. 952.)   Defendants Polygroup Limited (Macao Commercial Offshore), 
Polygroup Macau Limited (BVI), Polytree (H.K.) Co. Ltd., Polygroup Trading Limited 
(collectively, “Defendants”) submitted briefing in opposition to enhanced damages and in 
opposition to the motion for prejudgment and post-judgment interest.  For the reasons 
addressed below, the Court declines to enhance the jury award and grants the motion for 
prejudgment and post-judgment interest.                                   
                         BACKGROUND                                      
    Willis Electric filed this patent infringement action in 2015 alleging that Polygroup 
infringed various claims of several patents, including 
U.S. Patent No. 8,454,186
 (’186 
patent).  Polygroup asserted defenses of non-infringement and invalidity of these patents.  
After motion practice and inter partes review (IPR) proceedings challenging the validity of 
the asserted patents, see, e.g., Polygroup Ltd. MCO v. Willis Elec. Co., Ltd., 2021-1401, 

2021-1402, 
2022 WL 1183332
 (Fed. Cir. Apr. 20, 2022), the sole claim tried to the jury 
was claim 15 of the ’186 patent.                                          
    The jury trial commenced on January 8, 2024, before this Court.  On January 17, 
2024, the jury returned a unanimous verdict finding that Polygroup willfully infringed 
claim 15 of the ’186 patent.  The jury awarded $42,494,772 in damages.  Following the 
jury verdict, the Court requested supplemental briefing on the issue of whether enhanced 

damages should be awarded based on the willful infringement finding.  Also following the 
jury verdict, Willis Electric filed a motion for prejudgment and post-judgment interest.   
                           ANALYSIS                                      
I.   Willful Infringement and Enhanced Damages                            
    A.   Legal Standard                                                  

    The Court “may increase the damages up to three times the amount found or 
assessed.”    
35 U.S.C. § 284
.    Enhanced  damages  are  “designed  as  a  ‘punitive’  or 
‘vindictive’ sanction for egregious infringement behavior.”  Halo Elecs., Inc. v. Pulse 
Elecs., Inc., 
136 S. Ct. 1923, 1932
, 
195 L. Ed. 2d 278
 (2016).  “The sort of conduct 
warranting  enhanced  damages  has  been  variously  described  .  .  .  as  willful,  wanton, 

malicious,  bad-faith,  deliberate,  consciously  wrongful,  flagrant,  or  —  indeed  — 
characteristic of a pirate.”  
Id.
  Importantly, “[e]nhanced damages are generally only 
appropriate in egregious cases of misconduct.”  Presidio Components, Inc. v. Am. Tech. 
Ceramics Corp., 
875 F.3d 1369, 1382
 (Fed. Cir. 2017).                     
    The decision to award enhanced damages is committed to the court’s discretion.  
Halo Elecs., 
136 S. Ct. at 1934-35
.  In deciding whether to award enhanced damages, the 

court  considers  “the  particular  circumstances  of  the  case  to  determine  whether  it  is 
egregious.”  Presidio Components, 
875 F.3d at 1383
.  Even in cases where the jury finds 
willful infringement, a court is not required to award enhanced damages.  
Id. at 1382
. 
    Courts  traditionally  examine  the  Read  factors  in  deciding  whether  to  award 
enhanced damages: (1) whether the infringer deliberately copied the ideas or design of 
another;  (2)  whether  the  infringer,  when  he  knew  of  the  other’s  patent  protection, 

investigated the scope of the patent and formed a good-faith belief that it was invalid or 
that it was not infringed; (3) the infringer’s behavior as a party to the litigation; (4) 
defendant’s  size  and  financial  condition;  (5)  closeness  of  the  case;  (6)  duration  of 
defendant’s misconduct; (7) remedial action by the defendant; (8) defendant’s motivation 
for harm; and (9) whether defendant attempted to conceal its misconduct.  Read Corp. v. 

Portec, Inc., 
970 F.2d 816, 827
 (Fed. Cir. 1992).  The Read factors are “non-exclusive,” 
but provide a structure to the Court’s analysis.  Georgetown Rail Equip. Co. v. Holland 
L.P., 
867 F.3d 1229
, 1244-45 & n.6 (Fed. Cir. 2017).                      
    Several of the Read factors relate to issues “that were not before the jury and/or 
which the jury would not have been in a position to assess.”  Idenix Pharms. LLC v. Gilead 

Scis., Inc., 
271 F. Supp. 3d 694, 697
 (D. Del. 2017).  “Therefore, it is entirely appropriate, 
even required, for the Court to consider — based on its extensive familiarity with the entire 
course of this case, as well as what it observed a trial — where, notwithstanding the jury’s 
verdict  in  favor  of  [Willis  Electric],  substantial  contrary  evidence  was  presented  by 
[Polygroup].”  
Id.
  Indeed, the Court cannot substitute its factual determination for a jury’s 
willfulness finding.  Advanced Cardiovascular Sys., Inc. v. Medtronic, Inc., 
265 F.3d 1294, 1311
 (Fed. Cir. 2001).  However, this does not prevent the Court from “observing where, 
as the case may be, there was also substantial evidence presented by the willful infringer, 
where the jury may have made findings that were not supported by the record, and where 
the jury heard no evidence and cannot be presumed to have made a particular finding.”  
Idenix Pharms., 
271 F. Supp. 3d at 697
.                                   

    B.   Analysis                                                        
    The Court finds that, based on the totality of the circumstances, Polygroup did not 
engage in the type of egregious  misconduct warranting  enhanced damages under  
35 U.S.C. § 284
 and Halo.  Enhanced damages are generally appropriate only in “egregious 
cases of misconduct beyond typical infringement.”  Halo, 
136 S. Ct. at 1935
; see also 

Presidio Components, 
875 F.3d at 1382
.                                    
    Willis Electric argues several factors from the Read Corp. test support increasing 
damages, including evidence suggesting Polygroup may have deliberately copied Willis 
Electric’s patented “One Plug” artificial tree design, failed to form a good faith belief of 
non-infringement or invalidity, engaged in concerning litigation conduct, has substantial 

financial resources as the world’s largest artificial tree company, and did not attempt to 
switch to a non-infringing alternative until 2019.  
970 F.2d at 827
.  Willis Electric also 
cites the lengthy six-year infringement period and Polygroup’s rule against writing emails 
about intellectual property (IP) issues.                                  
    However, Polygroup counters that it independently developed its initial “Quick Set” 
tree designs before seeing the One Plug tree, and that its engineers reasonably believed the 

Quick Set trees did not infringe and the patent was invalid over prior art such as the Loomis 
patent.  Polygroup points to its pursuit of IPR challenges as evidence of its good faith 
invalidity position.  Polygroup further argues that both parties litigated aggressively, that 
artificial trees are a minor product line, and that it lacked egregious motivations or clear 
concealment of evidence warranting enhanced damages.                      
    The Court finds that Willis Electric’s copying evidence, while concerning, does not 

definitively show egregious infringement.  At most, the evidence indicates a company 
monitoring a competitor’s anticipated patent and aggressively developing a competing 
product, not “wanton and malicious pirac[y].”  Halo, 
136 S. Ct. at 1932
 (quoting Seymour 
v. McCormick, 
57 U.S. 480, 488
, 
14 L. Ed. 1024
 (1853)).  The Court credits Polygroup’s 
engineers’ good faith belief in non-infringement and invalidity based on their analysis and 

IPR petitions.  See Presidio Components, 
875 F.3d at 1382-83
 (noting courts need only 
“consider the particular circumstances of the case to determine whether it is egregious”).  
Willis  Electric’s  litigation  misconduct  assertions  do  not  clearly  show  extraordinary 
malfeasance.  See Halo, 
136 S. Ct. at 1932, 1934
.  And while the infringement duration 
was substantial, Polygroup’s preemptive redesign efforts in 2019 mitigate against deeming 

this an egregious case.  See Read Corp., 
970 F.2d at 827
.                 
    In sum, considering the totality of the circumstances, Polygroup’s conduct does not 
constitute  the  type  of  willful,  wanton,  malicious,  bad-faith,  deliberate,  consciously 
wrongful, flagrant, or “characteristic of a pirate” behavior required for enhanced damages 
under Section 284 and Halo.  
136 S. Ct. at 1932
.  The evidence fails to show the sort of 
egregious  infringement  behavior  or  “misconduct  beyond  typical  infringement” 

contemplated in Halo that would mandate increasing the award here.  
Id. at 1935
; see also 
Presidio Components, 
875 F.3d at 1382
.  Accordingly, enhanced damages are denied. 
II.  Prejudgment Interest                                                 
    “[P]rejudgment interest should ordinarily be awarded under [35 U.S.C.] § 284.”  
Gen. Motors Corp. v. Devex Corp., 
461 U.S. 648, 656
, 
103 S. Ct. 2058, 2063
 (1983).  “In 
the typical case an award of prejudgment interest is necessary to ensure that the patent 

owner is placed in as good a position as he would have been in had the infringer entered 
into a reasonable royalty agreement.”  
Id. at 655
.  The Court has “wide latitude in the 
selection of interest rates.”  Uniroyal, Inc. v. Rudkin-Wiley Corp., 
939 F.2d 1540, 1545
 
(Fed. Cir. 1991).  Section 284 does not specify the interest rate to be used, and “[a] variety 
of rates have been utilized by courts in patent cases, including statutory rates set by state 

statutes, the U.S. Treasury bill rate, the prime rate, the prime rate plus a percentage, and a 
rate on borrowed funds.”  Global Traffic Techs., LLC v. Emtrac Sys., Inc., 
2014 U.S. Dist. LEXIS 57840
, 
2014 WL 1663420
, at *15 (D. Minn. Apr. 25, 2014), aff’d in part, rev’d in 
part on different grounds, 
620 F. App’x 895
 (Fed. Cir. 2015).  “[C]ourts often use the 
statutory interest rate of the state in which they sit.”  
2014 U.S. Dist. LEXIS 57840
, [WL] 

at *16.  Prejudgment interest is awarded from the date of infringement to the date of 
judgment.  Nickson Indus., Inc. v. Rol Mfg. Co., 
847 F.2d 795, 800
 (Fed. Cir. 1988). 
    First,  the  Court  must  decide  what  interest  rate  should  be  used  in  calculating 
prejudgment interest.  Willis Electric requests that the Court award prejudgment interest of 
10% pursuant to 
Minn. Stat. § 549.09
.  Polygroup argues that 
Minn. Stat. § 334.01
, 
providing a maximum interest rate of 6%, is the appropriate rate to apply.  Applying a rate 

of 6% results in interest amounts ranging between $1-4 million, depending on whether the 
Court applies simple or compounding interest.                             
    Polygroup does not dispute that courts in the District of Minnesota have generally 
awarded interest at the 10% Minnesota statutory rate in patent cases over the last decade.  
However,  Polygroup  argues  that  
Minn. Stat. § 334.01
  should  govern  here  since 
prejudgment interest was otherwise allowed under federal patent law before 
Minn. Stat. § 549.09
 was enacted.  Willis Electric counters that 
Minn. Stat. § 334.01
 does not apply 
because damages were not readily ascertainable until determined by the jury at trial.  
    Second,  the  Court  must  consider  whether  any  circumstances  warrant  limiting 
prejudgment interest.  Polygroup argues that such interest should be denied or reduced 
given Willis Electric’s pursuit of frivolous claims and the excessive jury award.  Willis 

Electric contends that Polygroup fails to prove the required undue delay or prejudice for 
limiting interest.                                                        
    Considering  the  parties’  arguments  and  precedent  in  this  District  regarding 
prejudgment interest in patent cases, the Court finds that the 10% Minnesota statutory rate 
is most appropriate to apply here.  Schwendimann v. Arkwright Advanced Coating, Inc., 

No. 11-820, 
2018 U.S. Dist. LEXIS 127732
, 
2018 WL 3621206
, *22-23 (D. Minn. July 
30, 2018); August Tech. Corp. v. Camtek, Ltd., No. 05-1396, 
2015 U.S. Dist. LEXIS 15017
, 
2015 WL 520546
, at *8 (D. Minn. Feb. 9, 2015).  Courts routinely award interest at the 
Minn. Stat. § 549.09
 rate in patent infringement cases, and Polygroup has not presented 
sufficiently compelling reasons to depart from this standard practice.    

    While Polygroup cites 
Minn. Stat. § 334.01
 and argues damages were ascertainable, 
the record indicates significant disputes existed between the parties’ damages experts 
regarding applicable theories, comparable licenses, and reasonable royalty rates.  This 
supports that damages were not readily ascertainable until determined by the jury verdict.  
Therefore, 
Minn. Stat. § 549.09
 and its 10% rate governs.                 
    In addition, Polygroup fails to prove the undue delay or prejudice needed to limit 

prejudgment interest.  The record instead reflects reasonable diligence by Willis Electric 
in pursuing and prosecuting its infringement claims.  Much of the “delay” Polygroup 
complains  of  was  either  necessitated  by  court  schedules  or  resulted  directly  from 
Polygroup’s own IPR challenges.  Polygroup offers no concrete evidence of corresponding 
prejudice tied to these case events.                                      

    As such, the Court concludes that Willis Electric is entitled to prejudgment interest 
at the 10% Minnesota statutory rate based on the $42,494,772 reasonable royalty damages 
awarded by the jury.  Accrued interest shall be calculated from June 4, 2013 through the 
date of final judgment.                                                   
III.  Post-Judgment Interest                                              

    The Court must decide how much post-judgment interest to award Willis Electric.  
Under 
28 U.S.C. § 1961
(a), “[i]nterest shall be allowed on any money judgment in a civil 
case recovered in a district court.”  “Such interest shall be calculated from the date of the 
entry of judgment, at a rate equal to the weekly average 1-year constant maturity Treasury 
yield . . . for the calendar week preceding the date of judgment.”  
28 U.S.C. § 1961
(a).  
Post-judgment interest applies to both the amount awarded in damages and prejudgment 

interest.  See Travelers Prop. Cas. Ins. Co. of Am. v. Nat’l Union Ins. Co., 
735 F.3d 993, 1008
 (8th Cir. 2013) (citing Arthur Young & Co. v. Reves, 
937 F.2d 1310, 1338
 (8th Cir. 
1991)).                                                                   
    In its motion, Willis Electric requested post-judgment interest at the rate of 4.8%, 
based on the Treasury yield for the week prior to its filing on January 31, 2024.  The 
judgment in this case has not yet been entered.  Thus, consistent with Section 1961(a), the 

appropriate post-judgment interest rate will be the weekly average 1-year Treasury yield 
for the week preceding the Court’s entry of judgment.                     
    The Court grants Willis Electric’s motion for post-judgment interest at the weekly 
average Treasury yield rate, to be calculated from the date judgment is entered until 
satisfaction.  This post-judgment interest shall apply to the total judgment amount, 

including prejudgment interest, and any fee and cost awards.              

ORDER

    Based on the foregoing analysis and all the files, records and proceedings herein, IT 

IS HEREBY ORDERED that:                                                   
    1.   Plaintiff  Willis  Electric’s  reasonable  royalty  damages  of  $42,494,772 
awarded by the jury shall not be enhanced.                                
    2.   Plaintiff  Willis  Electric’s  Motion  for  Prejudgment  and  Post-Judgment 
Interest, (Dkt. 965), is GRANTED.                                         
         a.   The Court’s judgment order, to be entered following this order, shall 

     include the order that Willis Electric is awarded $42,494,772 in reasonable royalty 
     damages, plus prejudgment interest calculated at the 10% Minnesota statutory rate 
     from June 4, 2013 through the date of final judgment.               
         b.   The Court’s judgment order, to be entered following this order, shall 
    also include the order that Willis Electric is entitled to post-judgment interest at the 

    weekly average 1-year Treasury rate, accruing from the date of entry of judgment 
    until the judgment is satisfied.                                     

Dated:  March 8, 2024                   s/Joan N. Ericksen                                             
                                       Joan N. Ericksen                  
                                       United States District Judge      

Reference

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