September promises to be a busy month for ASX dividend investors as cash from recently declared dividends during the ASX reporting season begins to land in shareholders’ bank accounts.

But before those dividends can be paid, companies must first determine which investors are entitled to their next dividends.

To do this, they set a deadline, also called an ex-dividend date. If you buy shares on or after this date, those shares will not come with the final dividend payment.

Wednesday, tomorrow, nine companies from S&P/ASX 200 Index (ASX: XJO) will see their shares become ex-dividend.

In other words, today will be the last day to get the last dividends from these ASX 200 shares.

Let’s take a look at them, starting with the company with the highest dividend yield.

Insignia Financial Ltd. (ASX:IFL)

Upcoming dividend: 11.8 cents
Postage: 100%
Payment date: September 29
PRD: Yes
Rolling dividend yield: 6.9%

Formerly known as IOOF, Insignia delivered 59% growth in underlying net profit after tax (NPAT) in FY22. This helped the financial business of the ASX 200 to increase its ordinary dividends by 35% during the year, even despite a reduction in its payout ratio.

Viva Energy Group Ltd (ASX: VEA)

Upcoming dividend: 13.7 cents
Postage: 100%
Payment date: September 22
DPR: Nope
Rolling dividend yield: 5.7%

The ASX 200 energy share recently announced its half-year results, posting a 218% increase in underlying NPAT thanks to strong refining margins. As a result, Viva advanced its refining dividends, including them in the interim dividend instead of the final dividend.

Upcoming dividend: 6 cents
Postage: 100%
Payment date: September 21
DPR: Nope
Rolling dividend yield: 4.4%

Progress on its sustainable improvement program and an increase in COVID-related demand helped Healius double its underlying NPAT in FY22. Healthcare increased total dividends by 21%.

Upcoming dividend: 12 US cents
Postage: 0%
Payment date: September 28
DPR: Nope
Rolling dividend yield: 3.8%

Packaging company ASX 200 recently declared a dividend of 12 US cents in the fourth quarter, bringing total dividends for fiscal year 22 to 49 US cents, up 4% from a year earlier. Amcor also provided further returns to shareholders through share buybacks, repurchasing $600 million of stock in FY22.

Medibank Private Ltd (ASX: MPL)

Upcoming dividend: 7.3 cents
Postage: 100%
Payment date: September 29
DPR: Nope
Rolling dividend yield: 3.7%

Health insurer ASX 200 reported underlying NPAT growth of 9% in FY22, helping the company increase its annual dividend by 6% while slightly reducing its dividend payout ratio.

Brambles Limited (ASX:BXB)

Upcoming dividend: 12 US cents
Postage: 35%
Payment date: October 13
DPR: Yes
Rolling dividend yield: 2.6%

Brambles’ FY22 results beat expectations, with revenue up 9% and NPAT up 18% at constant currencies. The ASX 200 supply chain business increased its total dividends by 11% year-on-year and restored its DRP.

Upcoming dividend: 38 cents
Postage: 100%
Payment date: October 7
DPR: Nope
Rolling dividend yield: 2.5%

Insurance broker ASX 200 reported NPAT growth of 14% in FY22, supported by organic growth in its Australian brokerage and agency segments. But despite rising profits, AUB has maintained its full-year dividends in light of its potential $880 million acquisition of Tysers. Subject to final regulatory approvals, the acquisition is expected to be completed by the end of 2022.

Upcoming dividend: 21 cents
Postage: 100%
Payment date: October 4
DPR: Nope
Rolling dividend yield: 2.1%

During the year, SEEK increased its total dividend by 10%, with underlying NPAT from continuing operations climbing 81% in FY22. The ASX 200 stock saw record job posting volumes in the Australia and New Zealand (ANZ) region and volume growth across all markets in Asia.

IDP Education Group Ltd (ASX:IEL)

Upcoming dividend: 13.5 cents
Postage: 14%
Payment date: September 29
DPR: Nope
Rolling dividend yield: 1.0%

Finally, IDP saw a strong rebound in demand in FY22 after previously being bogged down by COVID-related challenges. The ASX 200 education business increased revenue 48% while adjusted NPAT jumped 120%. This helped the company increase its annual dividend by 10% from FY21.