Anomalies with account balance (paper trading)

Alpaca Trading
1

Over the past few months I’ve been experiencing many anomalies with paper account balance, I normally would just create a new paper account as I was early in development but now that I’ve progressed quite far, I need help understanding the problem. I’ve created many tools now just to track my account balance.

Paper Account: PA383ZL73M41

On my Alpaca paper account, account cash from the Trading API does not reconcile to net cash implied by FILL activities for trade date 2026-08-04.

Using only Alpaca API data (account snapshots + activities), I get:

Amount
Prior close cash (2026-08-03, 4:01 PM ET snapshot) $31,321.62
+ Net cash from all 2026-08-04 activities (36 FILL rows; FEE/CSD/CSW/INT/DIV = $0) +$2,009.10
= Expected close cash $33,330.72
Actual close cash (2026-08-04, 4:01 PM ET snapshot) $32,837.85
Unexplained gap −$492.87

This is not a third-party dashboard issue. Both numbers come from the Alpaca API at known timestamps.

What reconciles correctly

  • Positions: Prior close quantities + all 2026-08-04 FILL activities = Aug 4 close snapshot quantities (match).
  • FILL totals: 36 FILL activities — buys $16,079.87, sells $18,088.97, net +$2,009.10, fees $0.00.
  • Equity identity: At each snapshot, cash + positions market value = equity (internally consistent).
  • Partial fills: Some orders appear as multiple FILL rows (e.g. PCG, CNQ, USB). Aggregated notionals match; this does not explain the ~$493 cash gap.

How the data was collected

  1. Account snapshots via Trading API (GET /v2/account + positions), captured at:

    • 2026-08-03 close: 2026-08-03T16:01:01 ET — cash $31,321.62, equity $46,418.55
    • 2026-08-04 post-open: 2026-08-04T09:31:01 ET — cash $31,321.45 (consistent with prior close)
    • 2026-08-04 close: 2026-08-04T16:01:02 ET — cash $32,837.85, equity $46,139.82

  2. Activities via get_activities() for types FILL, FEE, CSD, CSW, INT, DIV on 2026-08-04 (filtered by transaction_time date).

  3. Cash impact per FILL: sell proceeds = +price × qty; buy cost = −price × qty.

Please explain the $492.87 cash discrepancy for 2026-08-04 on my paper account:

  1. Is there a missing or misclassified activity type not returned by the activities API?
  2. Is there a known paper-account cash ledger bug for split/partial fills?
  3. What is the authoritative cash balance for end of day 2026-08-04, and how should activities be summed to match it?
2

@Jeffrey_C The discrepancy you are seeing is due to the 10% tax withholding on the gross proceeds from sales of Publicly Traded Partnerships (PTPs). This is technically only deducted for non-US taxpayers, but paper trading doesn’t look at the actual owner details and just implements the “worst case”. The transactions can be seen in the account activities tab and are shown below.

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Does that make sense?

3

Yes, perfect. Thank you so much. Where can I see this table in my account?

4

@Jeffrey_C The account activities can be found by selecting Account -> Activities in the left-hand menu of the dashboard as shown below.

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1 Like
5

@Dan_Whitnable_Alpaca Hi Dan, please head over to my post “Consistant 6:30AM - 6:35AM unfilled marketable paper trade orders” and answer it please. Ive left several follow-ups.

6

Sorry, I missed that you already said it is in the Activities tab. A more appropriate question is how do I add Those columns. I see those withholdings but it’s not obvious what they map to.

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7

@Jeffrey_C Every time a PTP security is sold, 10% of the sale price is withheld. Each activity you see corresponds to a sale. Unfortunately the associated symbol doesn’t show up on the dashboard. However if you download the activities using the /activities endpoint, the activity record includes a symbol field.