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    855 Proton Rd San Antonio, TX 78258-4203

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    855 Proton Rd San Antonio, TX 78258-4203

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    • Medical Office Space
    • 12,719 SF
    • 2.66 lot acres
    Off-Market
    Last Sale Jan 16, 2026
    Property ID
    US83-3811315
    The Realmo ID is a unique identifier assigned to every property, incorporating country codes and precise geo-coordinates for 300x300-foot land blocks. It enables standardized data collection and seamless integration of disparate sources such as ownership, tax, title data and physical specifications. By aggregating current and historical records, the Realmo ID powers advanced analytics and delivers deep, verifiable insights for real estate professionals.
    Value Estimations
    $655,000
    Show details
    Cap Rate Potential
    Location Intelligence

    Current Use by Public Records

    • Gastroenterology Consultants of San Antonio / Medical Clinic
    • James F. Jackson, MD / Physician
    • Donna McMyler, MD / Physician
    • Michael J. Guirl, MD / Physician
    • Paresh P. Mehta, MD / Physician

    Property Details for 855 Proton Rd

    Year built
    1999
    Lot size
    2.66 lot acres
    Property size
    12,719 SF
    Property type
    Medical Office Space
    Property subtype
    Medical centers
    APN
    17429-002-0030
    APU
    174290020030

    Value Estimations

    based on Realmo’s proprietary methodology

    • AI approach

      Method
      Estimation
      ML approach
      $545,000

    • Comparable approach

      Method
      Estimation
      AI Estimate
      $767,000
      Market price range: $367k - $1.22M

    • Alternative Use

      Use
      Estimation
      MEDICAL BUILDING
      $880,000
      Current use
      OFFICE BUILDING
      $845,000
      Change: -4% Conversion: Easy
      APARTMENT HOUSE (5+ UNITS)
      $820,000
      Change: -7% Conversion: Moderate
      WAREHOUSE, STORAGE
      $750,000
      Change: -15% Conversion: Difficult

    Get a detailed, property-specific estimation — fast and free

    Location Insight

    • Map
    • Local Demand
    City
    San Antonio
    County
    Bexar
    State
    Texas
    Longitude
    -98.4808
    Latitude
    29.6127
    CBSA code
    41700
    CBSA name
    SAN ANTONIO, TX METROPOLITAN STATISTICAL AREA

    Property Tax & Assessments

    Tax date
    Tax Amount
    Assessed Land Value
    Assessed Improvement Value
    Total Assessed Value
    Applied Tax Rate
    Land Market Value
    Improvement Market Value
    Total Market Value
    2023
    $71,160
    $1,356,790
    $1,743,210
    $3,100,000
    -
    $1,356,790
    $1,743,210
    $3,100,000

    Comparable in this City

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      MEDICAL BUILDING • 30,202 SF
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      View Details
    • Value Estimation
      $1,250,000
      11,955 SF

      18818 Meisner Dr

      MEDICAL BUILDING • 11,955 SF
      18818 Meisner Dr, San Antonio, TX 78258-3568
      View Details
    • Value Estimation
      $2,100,000
      88,597 SF

      540 Madison Oak Dr

      MEDICAL BUILDING • 88,597 SF
      540 Madison Oak Dr, San Antonio, TX 78258-3943
      View Details
    • Value Estimation
      $1,120,000
      23,544 SF

      325 Sonterra Blvd

      MEDICAL BUILDING • 23,544 SF
      325 Sonterra Blvd, San Antonio, TX 78258-4054
      View Details
    • Value Estimation
      $785,000
      14,903 SF

      1130 Sonterra Blvd

      MEDICAL BUILDING • 14,903 SF
      1130 Sonterra Blvd, San Antonio, TX 78258-4235
      View Details
    • Value Estimation
      $885,000
      17,873 SF

      19272 Stone Oak Pkwy

      MEDICAL BUILDING • 17,873 SF
      19272 Stone Oak Pkwy, San Antonio, TX 78258-3371
      View Details

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    • $21 SF/Yr
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    855 Proton Rd
    San Antonio, TX 78258-4203
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    Realmo Value Estimations

    Realmo estimates a property’s market value using a proprietary methodology that incorporates public data and user-submitted information. This cumulative value is generated by integrating a variety of conventional and innovative methods. 

    Disclaimer

    These figures are not official appraisals and should not be used as a substitute for a valuation performed by a licensed appraiser.
    Actual market value may differ due to factors not captured in the data. Estimates are offered for informational purposes only, and users should conduct independent research before making financial or investment decisions.
    By using this feature, you acknowledge that Realmo is not responsible for actions taken based on these estimates.

    AI approach

    Realmo AI Method estimates property value using machine learning models trained on millions of comparable listings, transactions, and market signals. It analyzes property features, location intelligence data, and current market dynamics to predict the most probable market value in real time.

    Realmo CapRate Calculation

    Realmo calculates the Capitalization Rate (Cap Rate) to help estimate a property's potential return on investment. The Cap Rate is a fundamental metric in commercial real estate that measures the relationship between a property's net operating income and its market value.

    How We Calculate Cap Rate

    Cap Rate Formula:
    Cap Rate (%) = (Net Operating Income / Property Value) × 100

    Net Operating Income (NOI) Formula:
    NOI = Area × Lease Rate × (1 - Vacancy Rate) × (1 - Operating Expense Ratio)

    Components

    Net Operating Income (NOI) represents the annual income a property generates after operating expenses:

    • Area: Building square footage from property records
    • Lease Rate: Annual $/sqft based on market data for the property type and geographic location
    • Vacancy Rate: Percentage of unoccupied space based on market data for the property type and location
    • Operating Expense Ratio: Operating costs as a percentage of income, varies by property type

    Property Value is derived from:

    • Recent sale price (if available)
    • Statistical models using comparable sales
    • AI-powered valuation estimates

    Example Calculation

    For a 100,000 sqft Office Building:

    • Lease Rate: $25.00/sqft/year (market data for Office in this area)
    • Vacancy Rate: 8% (market data for Office in this area)
    • Operating Expense Ratio: 35% (typical for Office properties)
    • Property Value: $15,000,000

    Step 1: Calculate NOI

    NOI = 100,000 × $25.00 × (1 - 0.08) × (1 - 0.35)
    NOI = 100,000 × $25.00 × 0.92 × 0.65
    NOI = $1,495,000/year

    Step 2: Calculate Cap Rate

    Cap Rate = ($1,495,000 / $15,000,000) × 100
    Cap Rate = 9.97%

    Property Type Considerations

    Net Operating Income calculations vary by property type due to different operating expense ratios:

    • Office: Higher expenses (30-40%) for HVAC, utilities, maintenance
    • Retail: Moderate expenses (25-35%) for common area maintenance
    • Industrial/Warehouse: Lower expenses (15-25%) for minimal tenant services
    • Multifamily: Moderate expenses (35-45%) including property management
    • Self-Storage: Lower expenses (25-35%) due to minimal maintenance

    Market lease rates and vacancy rates are specific to each property type and geographic location, reflecting local market conditions.

    Disclaimer

    These calculations are estimates for informational purposes only and should not be used as a substitute for professional financial analysis or appraisal.

    • Cap Rate calculations depend on market data that may change over time
    • Actual operating expenses, lease rates, and vacancy rates may differ from market averages
    • Individual property conditions, lease terms, and tenant quality significantly impact actual NOI
    • Property value estimates are approximations and not official appraisals
    • Cap rates vary widely by market, property condition, and investment risk profile

    Professional Guidance Recommended: Before making any investment or financial decisions, consult with licensed appraisers, commercial real estate brokers, and financial advisors who can evaluate your specific property and circumstances.
    By using this feature, you acknowledge that Realmo is not responsible for investment decisions or actions taken based on these estimates.

    Cap approach

    Capitalization Method calculates value based on estimated net operating income (NOI) and applying a market-based capitalization rate (cap rate), we estimate what a typical investor might be willing to pay for it.

    Comparable approach

    Comparable estimate is based on recent sales of similar nearby properties, adjusted for factors like size, condition, and location.

    Relative

    Relative property class coefficient uses factors that account for typical price differences between various asset types (e.g., retail vs. industrial) to provide a more accurate market-aligned estimate.

    Geo

    Comparable Sales Method, enhanced by Geo coefficients — location-based adjustment factors that reflect differences in price levels across neighborhoods, cities, or regions ensuring a more accurate, market-sensitive valuation.

    Stat Estimate

    This method estimates value based on actual market adjusted recent (~5 years) sales of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all similar sales ($/sqft) are above this value
    • Range-to: 75% of all similar sales ($/sqft) are below this value
    AI Estimate

    This method estimates value based on AI market estimation of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all estimations ($/sqft) are above this value
    • Range-to: 75% of all estimations ($/sqft) are below this value
    Alternative use

    Estimate considers the property’s potential value if used for a different purpose-based on zoning, demand, and market feasibility.

    More about this property
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