What is Cost Basis?

2 min readPublished Jun 2, 2024

Explore how cost basis is calculated and its crucial role in determining capital gains, losses, and tax implications of investments.

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Cost basis is the original value of an asset for tax purposes, typically the purchase price adjusted for various factors such as stock splits, dividends, and return of capital distributions. This value is crucial for determining the capital gains or losses when the asset is sold, which in turn influences the taxes owed.

The cost basis of an investment includes the total amount invested initially, plus any associated commissions or fees paid during the purchase. For instance, if you buy a stock for $100 per share and pay a $5 commission, your cost basis would be $105 per share.

How is Cost Basis Used?

Cost basis plays a vital role in tax calculations by helping to determine capital gains or losses:

  • Capital Gains: Occur if the selling price of an asset exceeds its cost basis, resulting in a taxable gain.
  • Capital Losses: Happen if the selling price is less than the cost basis, leading to a deductible loss.

Understanding your cost basis can aid in effectively managing potential tax implications.

Methods to Calculate Cost Basis

There are several methods to calculate cost basis, each affecting how gains and losses are determined:

  • First-In, First-Out (FIFO): This method assumes the first assets purchased are the first sold.
  • Last-In, First-Out (LIFO): This method assumes the last assets purchased are the first sold.
  • Specific Identification: This allows investors to choose specifically which shares to sell, potentially optimizing tax outcomes.

Adjustments to Cost Basis

Adjustments to the cost basis may occur due to:

  • Stock Splits: Adjust the purchase price per share to reflect the split, altering the cost basis.
  • Reinvested Dividends: Increase the total investment amount, thus raising the cost basis.
  • Return of Capital: Decrease the cost basis since it’s considered a return on the investment.

Cost basis not only impacts individual investment decisions but also plays a significant role in broader financial and retirement planning. It’s a foundational concept that assists in making well-informed investment choices and planning for future financial needs.

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