Highlights

• Bioventix had one 70p Dividend go ex in the window, on 9 April 2026, paid on 24 April.

• An 80p payment went ex on 6 November 2025, five days before the twelve-month window opens.

• On a delayed price of 1,640p from 1 October 2026, the 70p equates to a 4.27% yield.

• The company develops and sells sheep monoclonal antibodies for diagnostic use worldwide, plus biomonitoring products and contract antibody services.

Count the dates carefully and Bioventix (LSE:BVXP) tells two stories. A 70p dividend sits inside the latest twelve months, while an 80p payment went ex just five days before the window opens. Which one is included changes the Yield dramatically, so it pays to see precisely how the figures were built.

The dividend dates

The in-window payment of 70p went ex-dividend on 9 April 2026, with the Record Date on 10 April and payment on 24 April 2026. The earlier payment, 80p, went ex on 6 November 2025, record date 7 November, paid 21 November 2025. Strictly applying a window that starts on 11 November 2025, only the 70p counts. No Special Dividend was found, and no further dividend has appeared so far. Holders of the company therefore see an interim in autumn and a final in spring.

Yield, with and without

At the delayed 1,640p price recorded on 1 October 2026, the 70p equates to a paid yield of 4.27%. Add the 80p from November 2025 and the combined 150p would equate to 9.15% on the same price, which is close to the 9.09% published elsewhere. That figure includes a payment outside the window, so it is not the trailing yield by the stated definition. An earlier price of 1,797p on 21 August 2026 shows how far the quote moved in six weeks.

A niche business

Bioventix develops, produces and sells sheep monoclonal antibodies for diagnostic use worldwide. It also offers environmental and industrial biomonitoring products and contract antibody services. The company is based in Farnham and is classed in healthcare and biotechnology. It trades on AIM, and the FTSE 250 and FTSE SmallCap lists checked did not include it. Its antibodies are used in diagnostic tests, so Demand follows the Volume of tests run by its customers.

Why dates matter for yield

A twelve-month window is a convenient rule, but it can make a yield look very different depending on where the payments fall. For Bioventix (LSE:BVXP), an interim paid just before the window opens drops out of the total, leaving only the final. If the next interim is paid in the autumn, the trailing figure would rise again once it is included. Investors should therefore compare the total over a full cycle of interim and final, instead of reading one number in isolation.

What to watch

A concentrated product base means a small number of customers and assays can shape results. The share price fell 3.53% in the session recorded on 1 October, so the yield is sensitive to the quote. Dividend cover should be checked in the company's filings, because a published Payout Ratio above 100% of earnings, if accurate, would mean payments exceed profit. An interim payment typically falls in the autumn, but none had been announced at the time of writing.

The healthcare angle

Diagnostic companies are exposed to testing volumes, regulation and the buying patterns of a small group of large customers. LSE:BVXP also depends on its intellectual property and the technical skill involved in producing antibodies. These features can lead to high margins and cash generation when demand is steady, which is one reason the company has been able to pay large dividends per share. The same features mean that results can change when a major customer alters its orders.

Concentration and cash

Companies with few products can earn high margins when the products sell well, but they depend on a narrow base. Bioventix sells antibodies used in specific diagnostic tests, so demand is linked to those tests and the customers who make them. A cash-rich Balance Sheet helps to smooth the effect of a quiet year and supports dividends, though a pattern of paying out more than profit would eventually deplete reserves.

Reading a window rule

The twelve-month window is a convention, and it produces a sharp contrast here. A reader who includes the 80p payment sees a yield above 9%, while one who applies the window sees 4.27%. Neither is wrong if the method is stated, but the first can mislead a new buyer, who would not receive the November 2025 payment. Always check the date of the last payment before relying on a yield for LSE:BVXP.

What to watch next

The next signal will be the autumn interim and the full-year results. A repeat of 80p and 70p would show stability, while a lower amount would indicate that the board is cautious. Investors should also look at cash balances, since a company that pays most of its profit out as dividends relies on a healthy cash position to continue.