RSU Cost Basis, Form 1099-B, and Form 8949: A Lot-by-Lot Reconciliation Guide
The RSU basis question is usually a reconciliation question. Payroll wage records, settlement value, broker proceeds, supplemental statements, and the exact lot sold must be connected before Form 8949 is prepared.
Source framework: plan documents and current official guidance.
Start with the exact RSU lot—not a broker basis field
A broker Form 1099-B may show proceeds for an RSU sale without showing every amount relevant to the taxpayer’s basis reconciliation. That can make the sale look more taxable than the underlying documents support. The first task is to identify the exact lot sold and connect it to the RSU settlement or delivery event, employer wage records, W-2, broker statement, and any supplemental information. The correct workpaper begins with documents, not a default basis field.
When RSUs are delivered and treated as compensation, the employer record may establish information needed to understand the later share basis. A broker can report the subsequent sale in a different system and may not incorporate employer payroll data. This is why payroll and broker documents must be read together. The goal is to determine what the employer treated as wages, what shares were delivered, which lot was sold, and what the broker reported for proceeds and basis.
For each RSU sale, create a one-page lot worksheet: award and settlement date, shares, wage record, W-2, broker proceeds, broker basis, supplemental data, sale date, and the supporting documents. Use the worksheet to prepare the current Form 8949 and Schedule D reporting. A qualified review is appropriate if basis is missing or inconsistent, the sale is material, multiple lots are involved, a broker transition occurred, or the employer records cannot be reconciled.
Connect settlement value and employer wage records
When RSUs are delivered and treated as compensation, the employer record may establish information needed to understand the later share basis. A broker can report the subsequent sale in a different system and may not incorporate employer payroll data. This is why payroll and broker documents must be read together. The goal is to determine what the employer treated as wages, what shares were delivered, which lot was sold, and what the broker reported for proceeds and basis.
Keep the grant and plan, settlement notice, value information, paystub, W-2, Form 1099-B, supplemental broker statement, trade confirmation, lot-selection history, and any Form 8949 workpaper. For each sale, record sale date, proceeds, broker basis, settlement or delivery date, payroll evidence, and the source for any reconciliation. If an account was transferred or a broker changed, preserve statements from both institutions.
Form 8949 and Schedule D reporting should follow current instructions and the actual documents for the lot. A basis or adjustment question is not solved by copying a generic code or assuming all RSU sales work the same way. Compare the Form 1099-B with the employer and supplemental records before software entry. If the forms conflict, retain the workpaper and obtain qualified help rather than selecting a number that only makes the screen balance.
Build the W-2, Form 1099-B, and supplemental statement file
Keep the grant and plan, settlement notice, value information, paystub, W-2, Form 1099-B, supplemental broker statement, trade confirmation, lot-selection history, and any Form 8949 workpaper. For each sale, record sale date, proceeds, broker basis, settlement or delivery date, payroll evidence, and the source for any reconciliation. If an account was transferred or a broker changed, preserve statements from both institutions.
Form 8949 and Schedule D reporting should follow current instructions and the actual documents for the lot. A basis or adjustment question is not solved by copying a generic code or assuming all RSU sales work the same way. Compare the Form 1099-B with the employer and supplemental records before software entry. If the forms conflict, retain the workpaper and obtain qualified help rather than selecting a number that only makes the screen balance.
For each RSU sale, create a one-page lot worksheet: award and settlement date, shares, wage record, W-2, broker proceeds, broker basis, supplemental data, sale date, and the supporting documents. Use the worksheet to prepare the current Form 8949 and Schedule D reporting. A qualified review is appropriate if basis is missing or inconsistent, the sale is material, multiple lots are involved, a broker transition occurred, or the employer records cannot be reconciled.
Use a documented Form 8949 reconciliation workflow
Form 8949 and Schedule D reporting should follow current instructions and the actual documents for the lot. A basis or adjustment question is not solved by copying a generic code or assuming all RSU sales work the same way. Compare the Form 1099-B with the employer and supplemental records before software entry. If the forms conflict, retain the workpaper and obtain qualified help rather than selecting a number that only makes the screen balance.
Noncovered lots, zero basis displays, same-day sales, sell-to-cover, multiple vesting dates, partial sales, corporate actions, broker transfers, a state move, and a W-2 mismatch can all require a more careful file. A tax notice risk is reduced by accurate documents and consistent reporting, not by hiding a sale or relying on an unsourced adjustment. Keep the exact statements used for the return.
Keep the grant and plan, settlement notice, value information, paystub, W-2, Form 1099-B, supplemental broker statement, trade confirmation, lot-selection history, and any Form 8949 workpaper. For each sale, record sale date, proceeds, broker basis, settlement or delivery date, payroll evidence, and the source for any reconciliation. If an account was transferred or a broker changed, preserve statements from both institutions.
Basis facts that make a generic answer unsafe
Noncovered lots, zero basis displays, same-day sales, sell-to-cover, multiple vesting dates, partial sales, corporate actions, broker transfers, a state move, and a W-2 mismatch can all require a more careful file. A tax notice risk is reduced by accurate documents and consistent reporting, not by hiding a sale or relying on an unsourced adjustment. Keep the exact statements used for the return.
For each RSU sale, create a one-page lot worksheet: award and settlement date, shares, wage record, W-2, broker proceeds, broker basis, supplemental data, sale date, and the supporting documents. Use the worksheet to prepare the current Form 8949 and Schedule D reporting. A qualified review is appropriate if basis is missing or inconsistent, the sale is material, multiple lots are involved, a broker transition occurred, or the employer records cannot be reconciled.
Keep the grant and plan, settlement notice, value information, paystub, W-2, Form 1099-B, supplemental broker statement, trade confirmation, lot-selection history, and any Form 8949 workpaper. For each sale, record sale date, proceeds, broker basis, settlement or delivery date, payroll evidence, and the source for any reconciliation. If an account was transferred or a broker changed, preserve statements from both institutions.
Create one workpaper for every RSU sale
For each RSU sale, create a one-page lot worksheet: award and settlement date, shares, wage record, W-2, broker proceeds, broker basis, supplemental data, sale date, and the supporting documents. Use the worksheet to prepare the current Form 8949 and Schedule D reporting. A qualified review is appropriate if basis is missing or inconsistent, the sale is material, multiple lots are involved, a broker transition occurred, or the employer records cannot be reconciled.
Keep the grant and plan, settlement notice, value information, paystub, W-2, Form 1099-B, supplemental broker statement, trade confirmation, lot-selection history, and any Form 8949 workpaper. For each sale, record sale date, proceeds, broker basis, settlement or delivery date, payroll evidence, and the source for any reconciliation. If an account was transferred or a broker changed, preserve statements from both institutions.
Noncovered lots, zero basis displays, same-day sales, sell-to-cover, multiple vesting dates, partial sales, corporate actions, broker transfers, a state move, and a W-2 mismatch can all require a more careful file. A tax notice risk is reduced by accurate documents and consistent reporting, not by hiding a sale or relying on an unsourced adjustment. Keep the exact statements used for the return.
RSU Cost Basis, Form 1099-B, and Form 8949 FAQs
For “Why does my Form 1099-B show zero basis for RSUs?,” the answer depends on the broker reporting method, employer wage records, settlement information, supplemental statement, and exact lot. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
For “How do I determine RSU cost basis?,” the answer depends on the settlement or delivery event, compensation treatment, W-2, broker lot, and current reporting workpaper. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
For “Do I need Form 8949 for an RSU sale?,” the answer depends on the Form 1099-B, proceeds, basis reconciliation, sale lot, and current filing instructions. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
For “Can RSUs be taxed twice if basis is wrong?,” the answer depends on the employer compensation event, broker sale reporting, lot history, and documented reconciliation. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
For “What is a supplemental broker statement for RSUs?,” the answer depends on additional transaction data that should be compared with the W-2, settlement, Form 1099-B, and plan records. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
For “How do I report a partial sale of RSU shares?,” the answer depends on the specific lot selected, delivery date, shares sold, proceeds, basis records, and remaining shares. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
For “What if my W-2 and 1099-B do not agree?,” the answer depends on the payroll record, settlement statement, broker data, supplemental statement, and lot-by-lot workpaper. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
For “When should RSU basis be reviewed before filing?,” the answer depends on zero basis, missing statements, large proceeds, multiple lots, a broker transfer, state facts, or inconsistent employer records. Start with the award or grant document, the exercise or settlement record, the relevant payroll statement, and the brokerage or transaction confirmation; each document may describe a different event. Put the dates and values in order before drawing a conclusion. A common mistake is to rely on only one portal screen or tax form and assume it captures the full tax treatment. The practical filing or planning consequence depends on how the employer reported the event, what later transaction occurred, and the current official instructions. If the records do not reconcile, the event crosses years or states, or the amount is material to your annual tax picture, preserve the documents and obtain qualified review before filing or making an election.
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Sources and scope
Use current official instructions and your plan documents for the transaction at issue. Key starting sources: https://www.irs.gov/publications/p525 · https://www.irs.gov/forms-pubs/about-form-6251 · https://www.irs.gov/forms-pubs/about-form-8949 · https://www.irs.gov/forms-pubs/about-form-3921.