SECOND AMENDMENT TO LOAN AND SECURITY AGREEMENT

Exhibit 10.28

SECOND AMENDMENT

TO

LOAN AND SECURITY AGREEMENT

THIS SECOND AMENDMENT to Loan and Security Agreement (this “Amendment”) is entered into this 25th day of March, 2011 by and between Silicon Valley Bank (“Bank”) and IMPINJ, INC., a Delaware corporation (“Borrower”) whose address is 701 N. 34th Street, Suite 300, Seattle, WA 98103.

RECITALS

A. Bank and Borrower have entered into that certain Loan and Security Agreement dated as of May 7, 2010 as amended by that certain First Amendment to Loan and Security Agreement dated as of February 1, 2011 (as the same may from time to time be further amended, modified, supplemented or restated, the “Loan Agreement”).

B. Bank has extended credit to Borrower for the purposes permitted in the Loan Agreement.

C. Borrower has requested that Bank amend the Loan Agreement to (i) permit Borrower to incur certain mezzanine debt to Bank, and (ii) make certain other revisions to the Loan Agreement as more fully set forth herein.

D. Bank has agreed to so amend certain provisions of the Loan Agreement, but only to the extent, in accordance with the terms, subject to the conditions and in reliance upon the representations and warranties set forth below.

AGREEMENT

NOW, THEREFORE, in consideration of the foregoing recitals and other good and valuable consideration, the receipt and adequacy of which is hereby acknowledged, and intending to be legally bound, the parties hereto agree as follows:

1. Definitions. Capitalized terms used but not defined in this Amendment shall have the meanings given to them in the Loan Agreement,

2. Amendments to Loan Agreement.

2.1 Section 2.6 (Mandatory Prepayment). New Section 2.6 is hereby added as follows:

“2.6 Mandatory Prepayment. If Borrower receives a notice of redemption election from the requisite stockholders of Borrower pursuant to the terms of its certificate of incorporation, as amended (the “Charter”), which requires Borrower to repurchase capital stock of such stockholders pursuant to the terms of its Charter and if Borrower is legally permitted to repurchase such capital stock under applicable law, then Borrower shall notify Bank of such redemption notice not less than twenty (20) days prior to the required date of repurchase of such capital stock pursuant to the terms of the Charter, and at Bank’s written election, Bank may require that Borrower be required to prepay all or a portion of the outstanding Obligations under this Agreement five (5) Business Days prior to the required date of repurchase of such capital stock pursuant to the terms of the Charter.”

2.2 Section 7.2 (Changes in Business, Management, Control, or Business Locations). Paragraph 1, subsection (c)(ii) of Section 7.2 is amended in its entirety and replaced with the following:

“(ii) consummate any transaction or series of related transactions in which the stockholders of Borrower who were not stockholders immediately prior to the first such transaction own more than forty percent (40%) of the voting stock of Borrower immediately after giving effect to such transaction or related series of such transactions (other than by the sale of Borrower’s equity securities in a public offering or to venture capital investors so long as Borrower identifies to Bank the venture capital investors prior to the closing of the transaction and provides to Bank a description of the material terms of the transaction).”

2.3 Section 7.7 (Distributions; Investments). Section 7.7 is amended in its entirety and replaced with the following:

“7.7 Distributions; Investments. (a) Pay any dividends or make any distribution or payment or redeem, retire or purchase any capital stock provided that (i) Borrower may convert any of its convertible securities into other securities pursuant to the terms of such convertible securities or otherwise in exchange thereof, (ii) Borrower may pay dividends solely in common stock; (iii) Borrower may repurchase the stock of former employees, directors or consultants pursuant to stock repurchase agreements so long as an Event of Default does not exist at the time of such repurchase and would not exist after giving effect to such repurchase, provided such repurchase does not exceed in the aggregate of Two Hundred Fifty Thousand Dollars ($250,000) per fiscal year and (iv) subject to the notice and mandatory payment provisions of Section 2.6 hereof, Borrower may repurchase capital stock pursuant to the terms of its Charter, or (b) directly or indirectly make any Investment other than Permitted Investments, or permit any of its Subsidiaries to do so.”

2.4 Section 8.6 (Other Agreements). Section 8.6 is amended in its entirety and replaced with the following:

“8.6 Other Agreements. There is, under any agreement to which Borrower or any Guarantor is a party with a third party or parties, (a) any default resulting in a right by such third party or parties, whether or not exercised, to accelerate the maturity of any Indebtedness in an amount individually or in the aggregate in excess of Two Hundred Fifty Thousand Dollars ($250,000); or (b) any default by Borrower or Guarantor, the result of which could have a material adverse effect on Borrower’s or any Guarantor’s business. Notwithstanding any provision of this Agreement or any Loan Document, (i) any non-payment default arising under any EX-IM Loan Documents shall not constitute an Event of Default hereunder unless the event giving rise to such default also separately constitutes an Event of Default pursuant to the terms of this Agreement and (ii) this Section 8.6 shall not be applicable to any Events of Default under the Mezzanine Loan Documents;”

2.5 Section 13 (Definitions). The following defined terms are hereby added to Section 13.1 of the Loan Agreement as follows:

“Charter” is defined in Section 2.6.

“Mezzanine Loan Agreement” means that certain Loan and Security Agreement by and between Borrower and Bank dated as of March 25, 2011.

“Mezzanine Loan Documents” all of the “Loan Documents” (as such term is defined in the Mezzanine Loan Agreement).

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2.6 Section 13 (Definitions). The following defined term in Section 13.1 of the Loan Agreement is amended in its entirety and replaced with the following

“Subordinated Debt” is (i) Indebtedness incurred by Borrower subordinated to all of Borrower’s now or hereafter indebtedness to Bank (pursuant to a subordination, intercreditor, or other similar agreement in form and substance satisfactory to Bank entered into between Bank and the other creditor), on terms acceptable to Bank and (ii) Indebtedness owing from Borrower to Bank pursuant to the Mezzanine Loan Documents.

2.7 Section 13 (Definitions). Subsection (a) of the defined term “Permitted Indebtedness” set forth in Section 13.1 is amended in its entirety and replaced with the following:

“(a) Borrower’s Indebtedness to Bank under this Agreement, the other Loan Documents and the Mezzanine Loan Documents;”

2.8 Section 13 (Definitions). Subsection (a) of the defined term “Permitted Liens” set forth in Section 13.1 is amended in its entirety and replaced with the following:

“(a) Liens existing on the Effective Date and shown on the Perfection Certificate or arising under this Agreement, the other Loan Documents or the Mezzanine Loan Documents;”

2.9 The Perfection Certificate attached hereto as Exhibit A hereby replaces the Perfection Certificate delivered on the Effective Date.

2.10 All references in the EX-IM Loan Agreement to the term Domestic Loan Agreement, shall be deemed to refer to the Domestic Loan Agreement as amended from time to time.

3. Limitation of Amendments.

3.1 The amendments set forth in Section 2, above, are effective for the purposes set forth herein and shall be limited precisely as written and shall not be deemed to (a) be a consent to any amendment, waiver or modification of any other term or condition of any Loan Document, or (b) otherwise prejudice any right or remedy which Bank may now have or may have in the future under or in connection with any Loan Document.

3.2 This Amendment shall be construed in connection with and as part of the Loan Documents and all terms, conditions, representations, warranties, covenants and agreements set forth in the Loan Documents, except as herein amended, are hereby ratified and confirmed and shall remain in full force and effect.

4. Representations and Warranties. To induce Bank to enter into this Amendment, Borrower hereby represents and warrants to Bank as follows:

4.1 Immediately after giving effect to this Amendment (a) the representations and warranties contained in the Loan Documents are true, accurate and complete in all material respects as of the date hereof (except to the extent such representations and warranties relate to an earlier dale, in which case they are true and correct as of such date), and (b) no Event of Default has occurred and is continuing;

4.2 Borrower has the power and authority to execute and deliver this Amendment and to perform its obligations under the Loan Agreement, as amended by this Amendment;

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4.3 The execution and delivery by Borrower of this Amendment and the performance by Borrower of its obligations under the Loan Agreement, as amended by this Amendment, have been duly authorized;

4.4 The execution and delivery by Borrower of this Amendment and the performance by Borrower of its obligations under the Loan Agreement, as amended by this Amendment, do not and will not contravene (a) any law or regulation binding on or affecting Borrower, (b) any contractual restriction with a Person binding on Borrower, (c) any order, judgment or decree of any court or other governmental or public body or authority, or subdivision thereof binding on Borrower, or (d) the organizational documents of Borrower,

4.5 The execution and delivery by Borrower of this Amendment and the performance by Borrower of its obligations under the Loan Agreement, as amended by this Amendment, do not require any order, consent, approval, license, authorization or validation of, or filing, recording or registration with, or exemption by any governmental or public body or authority, or subdivision thereof, binding on either Borrower, except as already has been obtained or made; and

4.6 This Amendment has been duly executed and delivered by Borrower and is the binding obligation of Borrower, enforceable against Borrower in accordance with its terms, except as such enforceability may be limited by bankruptcy, insolvency, reorganization, liquidation, moratorium or other similar laws of general application and equitable principles relating to or affecting creditors’ rights.

5. Counterparts. This Amendment may be executed in any number of counterparts and all of such counterparts taken together shall be deemed to constitute one and the same instrument.

6. Effectiveness. This Amendment shall be deemed effective upon (a) the due execution and delivery to Bank of this Amendment by each party hereto and (b) the due execution and delivery to Bank of the Mezzanine Loan Documents.

[Signature page follows.]

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be duly executed and delivered as of the date first written above.

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Exhibit A

Perfection Certificate

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Notes:

PERFECTION CERTIFICATE

The undersigned, the SVP of Finance and CFO of Impini, Inc. (the “Company”), hereby represents and warrants to you on behalf of the Company as follows:

a. The name of the Company as it appears in its current Articles or Certificate of Incorporation is: Impinj, Inc.

b. The federal employer identification number of the Company is: 91 ###-###-####

c. The Company is formed under the laws of the [State] [Country] of Delaware.

d. The organizational identification number of the Company is:             

e. The Company transacts business in the following jurisdictions (list jurisdictions other than jurisdiction of formation):             

f. The Company is duly qualified to transact business as a foreign entity in the following jurisdictions (list jurisdictions other than jurisdiction of formation): WA, CA, AR, TX, OR, IN, NJ, SC, NC, CO, TN, FL and internationally in UK, Italy, Malaysia, China

g. The following is a list of all other names (including fictitious names, d/b/a’s, trade names or similar names) currently used by the Company or used within the past five years:

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h. The following are the names of all entities which have been merged into the Company during the past five years:

i. The following are the names and addresses of all entities from whom the Company has acquired any personal property in a transaction not in the ordinary course of business during the past five years, together with the date of such acquisition and the type of personal property acquired (e.g., equipment, inventory, etc.):

a. The legal name of each subsidiary and parent of the Company is as follows. (A “parent” is an entity owning more than 50% of the outstanding capital stock of the Company. A “subsidiary” is an entity, 50% or more of the outstanding capital stock of which is owned by the Company.)

b. The following is a list of the respective jurisdictions and dates of formation of the parent and each subsidiary of the Company:

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c. The following is a list of all other names (including fictitious names, d/b/a’ s, trade names or similar names) currently used by each subsidiary of the Company or used during the past five years:

d. The following are the names of all corporations which have been merged into a subsidiary of the Company during the five years:

e. The following are the names and addresses of all entities from whom each subsidiary of the Company has acquired any personal property in a transaction not in the ordinary course of business during the past five years, together with the date of such acquisition and the type of personal property acquired (e.g., equipment, inventory, etc.):

a. The chief executive offices of the Company and its subsidiaries are presently located at the following addresses:

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b. The Company’s books and records and those of its subsidiaries are located at the following additional addresses (if different from the above):

c. The following are all the locations where the Company and its subsidiaries own, lease, or occupy any real property:

d. The following are all of the locations where the Company and its subsidiaries maintain any inventory, equipment, or other property:

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e. The following are the names and addresses of all warehousemen, bailees, or other third parties who have possession of any of the Company’s inventory or equipment or any of the inventory or equipment of its subsidiaries:

a. The Company and its subsidiaries own (or have any ownership interest in) the following kinds of assets. (If the answer is “Yes” to any of the following questions, please attach a schedule describing each such asset owned by the Company or its subsidiaries and identifying which party owns the asset.)

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b. The following is a list of material contracts to which the Company is a party (include any equipment leases) or in which the Company has an interest (including whether such contract has a nonassignability provision which would require the other party’s or another person’s consent to the granting of a security interest in such contract):

c. The following are all banks or savings institutions at which the Company and its subsidiaries maintain deposit accounts:

d. Does or is it contemplated that the Company will regularly receive letters of credit from customers or other third parties to secure payments of sums owed to the Company? The following is a list of letters of credit naming the Company as “beneficiary” thereunder:

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The Company’s and its subsidiaries’ property are subject to the following liens or encumbrances:

The Company and its subsidiaries are subject to regulation by the following federal, state or local government entity or any department, agency, or instrumentality thereof:

a. The following is a complete list of pending and threatened litigation or claims involving amounts claimed against the Company in an indefinite amount or in excess of $50,000 in each case: A former employee based in China that was laid off in 2010 has filed a claim seeking wrongful termination in a French court. He is seeking lost wages.

b. The following are the only claims which the Company has against others (other than claims on accounts receivable), which the Company is asserting or intends to assert, and in which the potential recovery exceeds $50,000: NA

The following tax assessments are currently outstanding and unpaid:

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The following broker handles the Company’s property insurance:

The following are the names and titles of the officers of the Company and its subsidiaries.

Company’s completed and executed IRS Form W9 is attached hereto as Exhibit A.

The following attorney will represent the Company in connection with the loan documents:

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The Company agrees to advise you of any change or modification to any of the foregoing information or any supplemental information provided on any continuation pages attached hereto, and, until such notice is received by you, you shall be entitled to rely upon such information and presume it is correct. The Company acknowledges that your acceptance of this Perfection Certificate and any continuation pages does not imply any commitment on your part to enter into a loan transaction with the Company, and that any such commitment may only be made by an express written loan commitment, signed by one of your authorized officers.

Date: 3/3/2011

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Continuation Page—Additional Information

3d & 3e. The Company has inventory at the following locations:

701 N 34^th Street, Suite 300, Seattle, WA 98103

Yusen Warehouse, 23119 66th Ave S, Kent, WA 98032 (Bailee Agreement in place)

Tasco (Yusen) Warehouse, Plot 93, Lintang Bayan Lepas 9, Taman Perindustrian Bayan Lepas, Fasa IV 11900 Bayan Lepas, Penang, Malaysia

Plexus Manufacturing, Bayan Lepas Free Industrial Zone, Phase IV, 11900 Bayan Lepas, Penang, Malaysia

Stars Microelectronics, Bang Pa-In Industrial Estate, 586 Moo 2, Tambol Klongjig, Amphur Bang Pa-In Ayutthaya 13160, Thailand

Corwil Technology Corporation, 1635 McCarthy Boulevard, Milpitas, CA 95035

Evans Analytical Group, 2710 Walsh Avenue, Santa Clara, CA 95051

FlipChip International, 3701 East University Dr., Phoenix, AZ 85034

FlipChip Millenium, No 351 Guo Shou Jing Road, Zhang Jiang Hi-Tech Park, Pudong New Area Shanghai 201203, China

4A. The company develops software and firmware for its products. This is not registered with the PO.

The company has licenses to patents related to its asset purchase of the reader chip business from Intel in July of 2008.

See attached for a list of patents and trademarks.

The company has licenses to do business several jurisdictions including Washington.

The company invests in government agency bonds like Fannie Mae and Freddie Mac.

4b. The following list of vendors have claims on some of the company’s assets as a result of financing equipment or computer hardware.

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The company licenses some its IP to a worldwide RFID standards organization known as EPC Global.

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Exhibit A

IRS Form W9

See attached.

IMPINJ, INC. TRADEMARKS & ISSUED PATENTS (3/2/2011)

Trademarks

Issued Patents