Form 637

(Rev. December 2013)

Department of the Treasury 

Internal Revenue Service 

Application for Registration 

(For Certain Excise Tax Activities)

▶ Information about Form 637 and its instructions is at www.irs.gov/form637.

OMB No. 1545-0014

Part I Identification of Applicant Type or print 

Name of individual, corporation, partnership, association, etc. Employer identification number 

Business name, if different from above Telephone number 

Mailing address (number, street, and room or suite no.; if P.O. box, see instructions) Fax number 

City or town, state, and ZIP code 

If you listed a P.O. box above, or if your street address is different from your mailing address, list your street address (including city or town, state, and ZIP code) 

Part II Activities. Enter the activity letter from the chart on pages 2–4 and a brief description of each activity for which you are applying 

for registration. Also, attach the Additional Information Required for each activity to which this application applies. 

Activity Letter Activity Description 

Part III General Information 

Section A—For All Applicants 

Answer all the questions below. Attach a separate sheet(s), as needed, to answer items 2b through 7. Identify each sheet with your 

name and employer identification number (EIN) at the top, and write the number of the item to which each answer applies. If any 

questions do not apply to you, explain why. 

1 a Are you or will you be required to file Form 720, Quarterly Federal Excise Tax Return? . . . . . . . Yes No

b Have you previously applied to be registered by any IRS office? . . . . . . . . . . . . . . . Yes No

c Have you, or any related entity, had a Certificate of Registry or Letter of Registration revoked by any IRS 

office? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No

d If you answered “Yes” to b or c, enter the name of the IRS office 

2 a List the date your business started ▶ Month Year 

b Explain in detail your business activity. 

3 For all other business entities to which you are related, list: 

a The name and EIN of the related entity, 

b The percentage of ownership, and 

c How you are related (for example, stock, partnership, etc.). 

4 List all addresses of current business operations (include out-of-state or foreign operations, if applicable). 

5 List the address where your books and records are kept (if different from the address in Part I). 

6 List the names and taxpayer identification numbers (TINs) of all business owners, corporate officers, members, or partners. 

7 List the name and phone number of a person whom we can contact about this application. 

Section B—For All Fuel Applicants 

If you are applying for fuel activities K, M, S, X, Y, AB, AF, AL, AM, CC, NB, SB, UA, UB, UP, or UV, you must answer questions 

8 and 9. 

8 Attach a copy of your last federal income tax return and other evidence that reflects financial responsibility such as your 

income statement, balance sheet, or bond rating. 

9 Describe any changes in your ownership or changes of controlling stock ownership in the past 2 years. If none, enter “None.” 

Also see Changes in Registration in the instructions. 

Go to Section C on Page 2 

For Privacy Act and Paperwork Reduction Act Notice, see instructions. Cat. No. 49952H Form 637 (Rev. 12-2013) 
Form 637 (Rev. 12-2013) Page 2 

Section C—For Certain Fuel Applicants 

If you are applying for fuel activities K, M, S, or Y, answer each question below by checking the “Yes” or “No” box. If you answer 

“Yes” to any of these questions, provide a full explanation. Attach additional sheets if needed. 

Have you or any related person (see Regulations section 48.4101-1(b)(5)) been:

10 Assessed any penalty under chapter 68 of the Internal Revenue Code (or similar provision of the law of any

state) for fraudulently failing to file any return or pay any tax, and the penalty has not been wholly abated, 

refunded, or credited? . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No

11 Assessed any penalty under chapter 68 of the Internal Revenue Code, and the penalty has not been wholly 

abated, refunded, or credited? . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No

12 Convicted of a crime under chapter 75 of the Internal Revenue Code (or similar provision of the law of any

state), or of conspiracy to commit such a crime, and the conviction has not been wholly reversed by a court 

of competent jurisdiction? . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No

13 Convicted, under the laws of the United States or any state, of a felony for which an element of the offense is 

theft, fraud, or the making of false statements, and the conviction has not been wholly reversed by a court of

competent jurisdiction? . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes No

14 Assessed any tax under section 4103 (willful failure to pay the tax imposed by section 4041(a)(1) or 4081) 

and the tax has not been wholly abated, refunded, or credited? . . . . . . . . . . . . . . . Yes No

15 Advised that your registration has been revoked? . . . . . . . . . . . . . . . . . . . Yes No

Sign 

Here 

Under penalties of perjury, I declare that I have examined this application, and accompanying schedules and statements, and, to the best of my knowledge 

and belief, they are true, correct, and complete. 

▲

Signature 

Type or print name below your signature. 

▲

Title ▲

Date 

Additional Information Required 

A Manufacturer of gas guzzler automobiles, 

sport fishing equipment (including fishing 

rods and fishing poles), fishing tackle 

boxes, bows, quivers, broadheads, 

points, arrow shafts, taxable tires, 

taxable medical devices, or vaccines. 

1. List all articles you manufactured. Include advertising brochures, if available. 

2. List the organizations or businesses (for example, state or local government or school) to 

which you intend to sell articles tax free. 

3. List the monthly volume of tax-free articles you intend to sell. Also, list the monthly volume 

of taxed articles you intend to sell. 

B Buyer of sport fishing equipment 

(including fishing rods and fishing poles), 

fishing tackle boxes, gas guzzler 

automobiles, bows, quivers, broadheads, 

points, taxable medical devices, or 

vaccines for further manufacture or for 

resale to a buyer for further manufacture. 

1. List articles you intend to purchase for further manufacturing or for resale for use by the 

buyer for further manufacturing. 

2. List the businesses that you will sell articles to for use in further manufacturing, if applicable. 

3. List your other types of sales of articles other than for further manufacturing. 

C Buyer of taxable tires for use on or in 

connection with the sale of another 

article the buyer manufactures and sells 

(1) for export, (2) to state and local 

governments, (3) to nonprofit educational 

organizations, or (4) as supplies for 

vessels or aircraft. 

1. List the type and weight of the tires you bought. 

2. List the articles you manufactured (1) on which the tires will be used or (2) in connection with 

which the tires will be sold. 

3. List the organizations or businesses with which you intend to have tax-exempt sales. 

D Buyer with a place of business in the 

United States purchasing taxable medical 

devices, vaccines, gas guzzler 

automobiles, taxable tires, sport fishing 

equipment (including fishing rods and 

fishing poles), fishing tackle boxes, bows, 

quivers, broadheads, points, or arrow 

shafts for export or for resale to a second 

purchaser for export. 

1. List the articles you intend to buy for export or resale to others for export. 

2. List the businesses to which you intend to sell articles for export. 

Form 637 (Rev. 12-2013) 

Activity Letter 
Form 637 (Rev. 12-2013) Page 3 

Additional Information Required 

E Buyer (other than state or local government) 

of gas guzzler automobiles for ambulance, 

law enforcement, or firefighting. 

Provide the general information for all applicants. 

F Nonprofit educational organization, 

other than a public school, buying 

taxable tires, certain heavy vehicles, 

sport fishing equipment (including 

fishing rods and fishing poles), fishing 

tackle boxes, bows, quivers, 

broadheads, points, or arrow shafts 

for its exclusive use. 

1. Provide a general description of the type of your educational facility, including faculty, 

curriculum, and student body. 

2. Provide a copy of the IRS determination letter granting your exemption from federal income tax. 

3. List products subject to federal excise tax you bought for the exclusive use of your organization

and how the products will be used in the operation of your organization. 

4. List activities (other than educational) conducted by the organization. 

I Buyer (other than nonprofit educational 

organization or state or local government) of 

taxable tires for use on certain intercity, local, 

or school buses. 

1. List types and weights of tires you bought. 

2. Describe the types of buses (intercity, local, or school) on which the tires are used. 

3. Describe how the buses are used in the operation of the business. 

K Buyer of kerosene for a feedstock 

purpose. 

List the type of kerosene you purchased; and describe the product and manufacturing process 

for which the kerosene will be used as a feedstock. 

M Blender of gasoline, diesel fuel (including 

a diesel-water fuel emulsion), or kerosene, 

producing a taxable fuel outside the bulk 

transfer/terminal system, including 

blenders of alcohol fuel mixtures, 

alternative fuel mixtures, biodiesel 

mixtures, and renewable diesel mixtures. 

1. List the products you bought or produced for blending with gasoline, diesel fuel, or kerosene. 

2. List the annual volume of products you bought for blending. 

3. List the annual volume of blended taxable fuel you produced. 

Q First retail seller of certain heavy 

vehicles. 

1. Describe the heavy vehicles you intend to sell. 

2. Describe the exempt sales of the heavy vehicles you intend to make. 

S Enterer, position holder, refiner, 

terminal operator, or throughputter of 

gasoline, diesel fuel (including a 

diesel-water fuel emulsion), or 

kerosene, or industrial user of gasoline. 

1. List the annual volume of gasoline, diesel fuel, and kerosene you entered into the United States 

or produced. 

2. List the locations and a description of your refineries, terminals, and pipelines. 

3. List the names and addresses of any person(s) who will be acting for you as an agent or 

broker in entering, buying, selling, or transporting any fuel. 

4. List the business entities to whom you sell, and with which you buy, trade, transfer, or 

exchange any gasoline, diesel fuel, and kerosene. 

5. Provide the annual volume of gasoline, diesel fuel, and kerosene you buy, sell, trade, 

transfer, or exchange. 

V Manufacturer, importer, or buyer of 

ozone-depleting chemicals (ODCs) 

for export. 

1. List the ODCs you import or manufacture for export. 

2. List the companies from which you buy ODCs for export. 

3. List the number of pounds for each type of ODC you exported in this calendar year and an 

estimate for next calendar year. 

4. List your export locations, and list your production allowance, consumption allowance, 

export allowance, and export percentage as set by the Environmental Protection Agency. 

X Pipeline operator or vessel operator 

(including certain deep-draft vessels) 

within the bulk transfer/terminal system. 

1. Schematic or map of your pipeline locations. 

2. Names and addresses of facilities served by your pipeline or vessel. 

3. Number, description, and capacities of your vessels used to transport taxable fuel. 

Y Buyer of kerosene for its use in 

commercial aviation (other than 

foreign trade). 

1. List the quantity, types, and gross take-off weights of all aircraft you own and/or operate. 

Include the countries of registration. Aircraft that you operate but that are owned by other 

persons should be clearly designated. Information should be included as to the operating 

arrangements. 

2. List the average number of operating hours (per month) of each aircraft that is listed in item 1. 

Show the number of hours for commercial aviation (other than foreign trade) and noncommercial

aviation. 

3. If you maintain kerosene storage facilities, list the location and capacity of each facility.

AB Producers and importers of 

agri-biodiesel. 

1. List the annual volume of agri-biodiesel you produced in or entered into the United States. 

2. List the locations and a description of your production facilities. 

3. List the names and addresses of any person(s) who will be acting for you as an agent or 

broker in entering, buying, selling, or transporting any agri-biodiesel. 

4. List the business entities to whom you sell and with which you buy, trade, transfer, or 

exchange any agri-biodiesel. 

5. Provide the annual volume of agri-biodiesel you buy, sell, trade, transfer, or exchange. 

AF Producers and importers of alcohol. 1. List the annual volume of alcohol you produced in or entered into the United States. 

2. List the locations and a description of your production facilities. 

3. List the names and addresses of any person(s) who will be acting for you as an agent or 

broker in entering, buying, selling, or transporting any alcohol. 

4. List the business entities to whom you sell and with which you buy, trade, transfer, or 

exchange any alcohol. 

5. Provide the annual volume of alcohol you buy, sell, trade, transfer, or exchange. 

Form 637 (Rev. 12-2013) 

Activity Letter 
Form 637 (Rev. 12-2013) Page 4 

Additional Information Required 

AL Alternative fueler that sells for use or 

uses alternative fuel as a fuel in a 

motor vehicle or motorboat. 

Provide the general information for all applicants. 

AM Alternative fueler that produces an 

alternative fuel mixture that is sold for 

use or used in the alternative fueler’s 

trade or business. 

Provide the general information for all applicants. 

BC Qualified blood collector organization 

buying taxable fuel, taxable tires, and 

certain heavy vehicles; claiming 

exemption from the communications 

tax and heavy highway vehicle use 

tax; or to claim a credit or payment of 

certain excise taxes, for its exclusive 

use in the collection, storage, or 

transportation of blood. 

1. Provide a general description of your blood collection activity. 

2. Provide a copy of the IRS determination letter granting you an exemption from federal income 

tax under section 501(a) as an organization described in section 501(c)(3). 

3. Provide evidence of your registration with the Food and Drug Administration as a blood 

collector. 

SB Producers of second generation biofuel. 1. List the annual volume of cellulosic biofuel (including second generation biofuel) you produced in 

the United States. 

2. List the plant material you used to produce the cellulosic biofuel (including second generation 

biofuel). 

3. List the locations and a description of your production facilities. 

4. List the names and addresses of any person(s) who will be acting for you as an agent or 

broker in buying, selling, or transporting any cellulosic biofuel (including second generation biofuel). 

5. List the business entities to whom you sell and with which you buy, trade, transfer, or 

exchange any cellulosic biofuel (including second generation biofuel). 

6. Provide the annual volume of cellulosic biofuel (including second generation biofuel) you buy, sell, 

trade, transfer, or exchange. 

CC Credit card issuer that issues credit 

cards for sales of taxable fuel to a state 

or local government for its exclusive 

use or for sales of gasoline to a 

nonprofit educational organization for 

its exclusive use. 

Provide the general information for all applicants. 

NB Producers and importers of 

biodiesel (other than agri-biodiesel) 

and renewable diesel. 

1. List the annual volume of biodiesel and renewable diesel you produced in or entered into the 

United States. 

2. List the locations and a description of your production facilities. 

3. List the names and addresses of any person(s) who will be acting for you as an agent or 

broker in entering, buying, selling, or transporting any biodiesel and renewable diesel. 

4. List the business entities to whom you sell and with which you buy, trade, transfer, or 

exchange any biodiesel and renewable diesel. 

5. Provide the annual volume of biodiesel and renewable diesel you buy, sell, trade, transfer, 

or exchange. 

QR Qualified retailer of diesel fuel or 

kerosene sold in Alaska for nontaxable 

uses. 

Provide the general information for all applicants. 

UA Ultimate vendor that sells kerosene 

for use in aviation. 

Provide the general information for all applicants. 

UB Ultimate vendor that sells undyed 

diesel fuel or undyed kerosene for 

use in certain intercity and local buses. 

Provide the general information for all applicants. 

UP Ultimate vendor that sells kerosene 

from a blocked pump. 

1. Describe the blocked pumps you used to sell kerosene in your business. 

2. List the location of your blocked pumps. 

UV Ultimate vendor that sells (a) undyed 

diesel fuel or undyed kerosene to a 

state or local government for its 

exclusive use, or (b) gasoline (including 

aviation gasoline) to a state or local 

government for its exclusive use or to 

a nonprofit educational organization for 

its exclusive use. 

Provide the general information for all applicants. 

Form 637 (Rev. 12-2013) 

Activity Letter 
Form 637 (Rev. 12-2013) Page 5 

Section references are to the Internal Revenue Code unless 

otherwise noted. 

Future Developments 

The IRS has created a page on IRS.gov for Form 637 and its 

instructions at www.irs.gov/form637. You can find information 

about any recent developments affecting Form 637 (such as 

legislation enacted after we release it) on that page.

What's New

• New activity letter SB now includes second generation biofuel. 

Current CB registrants will not need to reapply for the new SB

registration. Activity letter CB is removed because it is no longer 

applicable. 

• Activity letter QR is added for qualified retailers of diesel fuel 

or kerosene sold in Alaska. You do not need to reapply if you 

have already been issued a correspondence letter of registration 

as a qualified retailer. 

• Activity letter W is removed because it is no longer applicable.

General Instructions 

Purpose of Form 

Use Form 637 to apply for excise tax registration for activities 

under sections 4101, 4222, and 4682. See the chart on pages 

2–4 for the list of activities. Each business unit that has, or is 

required to have, a separate employer identification number 

(EIN) is treated as a separate person. 

The following persons must be registered: 

• Pipeline operator or vessel operator: Activity Letter X. 

• Enterers, position holders, refiners, and terminal operators: 

Activity Letter S. 

• Blenders: Activity Letter M. 

• Producers or importers of alcohol, agri-biodiesel, and 

biodiesel (including renewable diesel): Activity Letters AF, AB, 

and NB respectively. 

• Producers of second generation biofuel: Activity Letter SB.

Current CB registrants will not need to reapply for new SB

registrations.

Pub. 510, Excise Taxes, has more information regarding 

registrations. 

Penalty 

The penalty for failure to register, if you are required to register, is 

$10,000 for the initial failure, and $1,000 for each day following that 

you fail to register. The penalty applies unless the failure to register 

is due to reasonable cause. 

How To Apply 

Complete Form 637 and submit it with the required additional 

information described on the chart on pages 2–4. You may use 

additional sheets for your explanations. Be sure to write your 

name and EIN on each sheet you attach. You must send all of 

the required information or the processing of your application 

will be delayed. The IRS will ask you for additional information if 

needed, or you may provide additional information at any time. 

The application must be reviewed and approved before you 

are registered for any activity. The review may include 

inspection of your premises during normal business hours 

without advance notice. If your application is approved, the IRS 

will issue a Letter of Registration. The letter will include the 

activities you are registered for, the effective date of the 

registration, and your registration number. A copy of Form 637 

is not a Letter of Registration. If your application is denied, you 

will be notified in writing by the IRS that the application has 

been denied and the reason for the denial. 

Employer Identification Number (EIN) 

Enter your EIN. If you do not have an EIN, you may apply for 

one online. Go to the IRS website at 

www.irs.gov/businesses/small and click on the “Employer ID 

Numbers (EINs)” link. You may also apply for an EIN by calling 

1-800-829-4933, or you can fax or mail Form SS-4, Application 

for Employer Identification Number, to the IRS.

P.O. Box 

If the Post Office does not deliver mail to your street address 

and you have a P.O. box, show the box number instead of the 

street address. 

Signature 

Form 637 must be signed by a person with authority to bind the 

applicant. 

Where To Apply 

Send Form 637 to: 

Department of the Treasury 

Internal Revenue Service 

Excise Operations Unit- Form 637 

Cincinnati, OH 45999

Changes in Registration 

If an IRS office has issued you a Certificate of Registry or a 

Letter of Registration that is still in effect for an activity, you do 

not have to reapply for registration for that activity unless 

notified to do so. However, see Reregistration for Fuel Activities 

below. To confirm the status of a registration, visit 

www.irs.gov/app/exciseTax/. To apply for another activity or 

to cancel a registration, you must contact the IRS office in which 

you are registered. 

Notify the IRS office within 10 days if any information 

submitted with an application changes. This includes, but is not 

limited to, address changes or changes in business activities. A 

registrant may not sell, lease, or otherwise allow another person 

to use its registration. 

Reregistration for fuel activities. You must reregister with the 

IRS if there is a change of more than 50% of the ownership of a 

registrant and you are registered for activity letters K, M, S, Y, 

AB, AF, SB, or NB. In this instance, a change in ownership 

means that after a transaction (or series of transactions), more 

than 50% change of the ownership interests in, or assets of, a 

registrant are held by persons other than persons who held 

more than 50% of such interests or assets before the 

transaction (or series of transactions). Reregistration does not 

apply to companies whose stock is regularly traded on an 

established securities market. If you fail to reregister as 

required, see Penalty above. 

To reregister, send a newly completed Form 637 to the 

address under Where To Apply above. On line 1d, enter your 

current registration number. The IRS will revoke the current 

registration number and issue a new registration to the new 

ownership (registrant). 

Additional Registration Information 

For registration relating to: 

• Taxable fuel, see Regulations section 48.4101-1. 

• Exports of ozone-depleting chemicals, see Regulations 

section 52.4682-5. 

• All other articles, see Regulations section 48.4222(a)-1. 
Form 637 (Rev. 12-2013) Page 6 

The following notices provide additional guidance. 

• Notice 2005-4 (Public Law 108-357 fuel taxes). You can find 

Notice 2005-4 on page 289 of Internal Revenue Bulletin (IRB) 

2005-2 at www.irs.gov/pub/irs-irbs/irb05-02.pdf. It's modified 

by Notices 2005-24, 2005-62, and 2005-80.

• Notice 2005-24 (modifies Notice 2005-4); on page 757 of IRB 

2005-12 at www.irs.gov/pub/irs-irbs/irb05-12.pdf. 

• Notice 2005-62 (modifies Notice 2005-4); Biodiesel and 

Aviation-Grade Kerosene; on page 443 of IRB 2005-35 at 

www.irs.gov/pub/irs-irbs/irb05-35.pdf. 

• Notice 2005-80 (modifies Notice 2005-4); on page 953 of IRB 

2005-46 at www.irs.gov/pub/irs-irbs/irb05-46.pdf. 

• Notice 2006-92 (alt. fuel credit/tax; blood collectors); on page 

774 of IRB 2006-43 at www.irs.gov/pub/irs-irbs/irb06-43.pdf. 

• Notice 2008-110 (biodiesel; cellulosic biofuel) on page 1298 of 

IRB 2008-51 at www.irs.gov/irb/2008-51_IRB/index.html.

• Treasury Decision (T.D.) 9604 and Notice 2012-77 (medical 

device tax) on pages 730 and 781, respectively, of I.R.B. 

2012-52 at www.irs.gov/irb/2012-52_IRB/ar10.html.

Privacy Act and Paperwork Reduction Act Notice. We ask 

for the information on Form 637 to carry out the Internal 

Revenue laws of the United States. We need it to figure and 

collect the right amount of tax. Subtitle D of the Internal 

Revenue Code, Miscellaneous Excise Taxes, imposes certain 

excise taxes. Section 4101 requires certain persons to register 

for excise taxes on fuel, as imposed by sections 4041 and 4081. 

Sections 4101, 4222, and 4682 allow certain other 

manufacturers, sellers, or purchasers to register to be eligible 

for credits or to be exempt from the excise tax on taxable 

articles. If you are required to register under section 4101 or if 

you elect to register for credits and/or exemption, you are 

required to provide the information requested on this form. 

Failure to provide this information may subject persons required 

to register to penalties, and may delay or prevent the processing 

of a voluntary registration for credits or exemption; providing 

false information may subject you to penalties. Section 6109 

requires you to provide the requested identification numbers. 

You are not required to provide the information requested on 

a form that is subject to the Paperwork Reduction Act unless 

the form displays a valid OMB control number. Books or 

records relating to a form or its instructions must be retained as 

long as their contents may become material in the 

administration of any Internal Revenue law. 

Generally, tax returns and return information are confidential, 

as required by section 6103. However, section 6103 allows or 

requires the IRS to disclose or give such information to the 

Department of Justice for civil and criminal litigation; to cities, 

states, the District of Columbia, and U.S. commonwealths and 

possessions to administer their tax laws; and to other countries 

under a tax treaty. We may also disclose this information to 

federal and state agencies to enforce federal nontax criminal 

laws, or to federal law enforcement and intelligence agencies to 

combat terrorism. 

The time needed to complete and file Form 637 will vary 

depending on individual circumstances. The estimated average 

time is Recordkeeping, 7 hr., 39 min.; Learning about the law 

or the form, 1 hr., 37 min.; Preparing and sending the form to 

the IRS, 4 hr., 13 min. 

If you have comments concerning the accuracy of these time 

estimates or suggestions for making Form 637 simpler, we 

would be happy to hear from you. You can send your comments 

to:

Internal Revenue Service 

Tax Forms and Publications Division 

SE:W:CAR:MP:TFP 

1111 Constitution Ave. NW, IR-6526 

Washington, DC 20224

Do not send Form 637 to this address. Instead, see Where To 

Apply, earlier.