You log into EquatePlus, check your bp shares, and there it is. A nice clear figure showing the cost basis for each holding. Simple, right?
Not quite.
In recent weeks, we’ve had a few conversations where, quite understandably, the starting point is that the EquatePlus figure shown for each fund tranche is the capital gains tax (CGT) calculation pooled cost. The problem? That number often represents something quite different from what HMRC actually requires.
What EquatePlus shows you
When your bp shares vest and become unrestricted, EquatePlus assigns them a cost. This is usually the market value when they vested, the same figure used to calculate your income tax.
It’s useful for tracking what happened at vesting. But it’s not your CGT cost basis.
What HMRC actually needs
For capital gains tax, UK tax law requires the pooled average cost of all your share holdings.
This calculation includes:
- All your bp share acquisitions, however you got them
- Shares transferred from a spouse (keeping their original cost, not a new value)
- Shares bought through reinvested dividends
- Previous sales (these reduce the pool but don’t change the average cost per share)
- Shares from different schemes acquired at different times
- Different tax rules that applied when you bought various tranches
The result is a rolling average cost that changes with each transaction. It’s not the neat figure EquatePlus displays.
Why this matters
Getting your cost basis wrong directly affects:
- How much capital gains tax you pay
- Whether you’re making the right decisions about which shares to sell and when
- Your tax planning strategy
- Your HMRC compliance
We’ve seen cases where executives have significantly over or understated their CGT liability because they used the EquatePlus figure instead of calculating the true pooled cost.
The complexity builds over time
If you’ve been building up bp shares for years through GSVPs, ISVPs, Sharesave, Share Match, and bonus arrangements, your pooled cost calculation gets complex fast.
Each time you buy shares, they join the pool. Each sale means working out the average cost at that moment. Spouse transfers, dividend reinvestments, and corporate actions all affect it.
For bp employees who’ve been with the company for ten years or more, calculating this manually isn’t practical. The scope for error is huge.
What you should do
First, don’t assume the EquatePlus figure is your CGT basis. It might be close in simple cases, but it’s rarely the complete picture.
Second, if you’re planning to sell a lot of shares, or you’ve built up holdings over many years through various schemes, get the calculation done properly.
We work with tax specialists who calculate pooled share costs for bp shareholders regularly. They’ve seen every variation bp’s share schemes can create. Their calculations give you:
- Accurate pooled cost basis for CGT
- Documentary evidence for HMRC if needed
- Clarity on what you’ll actually owe when you sell
- Peace of mind you’re getting it right
The bottom line
That cost figure in EquatePlus? It’s useful information, but it’s not the full story for capital gains tax.
Getting your share cost basis right means making informed decisions, planning tax efficiently, and making sure you’re not leaving money on the table or short-changing HMRC.
Who can you think of that’s planning to sell bp shares in 2026? Share this article with them. Understanding the true cost basis matters when calculating capital gains tax.
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This is for educational purposes only. It’s not personal tax advice and we’re not recommending any specific course of action. Everyone’s situation is different, and decisions about share sales and tax calculations depend on individual circumstances including your complete share acquisition history, previous sales, spouse transfers, and other factors. You should consider seeking professional tax advice before making decisions about share sales and capital gains tax calculations.
While we have extensive experience helping bp employees and alumni optimise their benefits, Emery Little operates independently and is not affiliated with or endorsed by the bp group, including BP Pension Trustees Limited, on behalf of the BP Pension Fund. This allows us to provide objective, independent guidance focused solely on your best interests.
