A city of San Diego sales tax hike could be trending toward voter approval, despite still trailing in the latest vote totals posted by election officials early Wednesday morning. Supporters believe Measure E — a one-cent sales tax increase that would generate about $400 million annually — is highly likely to surpass the simple majority it needs for approval once all the votes are counted. They say reasons for optimism include the relatively large number of ballots left to be counted, city voting trends in recent years and a rush of late spending by supporters on ads and mailers. They’re confident those late ads and mailers swayed the votes of people casting their ballots late in the process — the same votes that the registrar will be counting and adding to the totals in coming days. But even without that late rush of spending, supporters say recent city voting trends make them confident. More conservative, anti-tax voters in the city have previously tended to return their ballots early, while liberal voters less opposed to tax hikes have tended to return their mail ballots later. That trend helped 2022’s Measure B, a city ballot measure asking voters whether the city should begin charging a fee for trash pickup at single-family homes. The morning after Election Day in 2022, Measure B was trailing 106,961 to 104,944. But it gained ground with each daily vote total update, eventually winning with 203,223 “yes” votes to 199,384 “no” votes — a margin of victory of just under 1 percentage point. And that was in a smaller turnout, non-presidential election, when there were fewer votes still remaining to be counted after election night that could help make up ground. Just under 200,000 city of San Diego votes were left to be counted after Election Day in 2022, while there are an estimated 250,000 city of San Diego votes left to be counted this time around. But Measure E is still facing a steeper vote deficit. Measure B was trailing by 2,017 votes after Election Day in 2022 but eventually won with a 3,839-vote lead once all ballots were counted. Measure E currently trails by 5,262 votes. One encouraging trend for supporters is that Measure E gained on Election Day. It was trailing by 8,208 votes when the first totals were posted just after 8 p.m. Tuesday, but that had shrunk to 5,262 by the final post just before 3 a.m. Wednesday. The measure now trails 50.72 percent to 49.28 percent. The roughly 250,000 city votes that the registrar estimates remain to be counted — 40% of the projected 590,000 outstanding ballots countywide — is a relatively large number. With just over 364,000 votes counted for and against Measure E so far, that means as many as roughly 40% of votes for and against Measure E may not have been counted yet. Mike Zucchet, leader of the campaign supporting Measure E, said Wednesday that he still expects the measure to pass. “With more than a third of ballots yet to be counted, and the trend already heading in the right direction, we remain confident that a majority of San Diego voters supported this measure,” said Zucchet, who leads the city’s largest labor union. “That result will be good news for our neighborhoods, aging infrastructure and essential city services.” Haney Hong, leader of the Measure E opposition, conceded Wednesday that the measure’s fate is too close to call. “It will take time to see the end results,” said Hong, chief executive of the San Diego County Taxpayers Association. Mayor Todd Gloria, who spearheaded Measure E along with Councilmember Raul Campillo, said late Tuesday that he remained optimistic. The same factors could also help Measure G, a half-cent countywide sales tax hike that would pay for transportation projects. But Measure G trails by more than 30,000 votes. It’s unclear whether voters in more conservative suburban and rural areas will vote in the same way as city residents. Staff writer Kristen Taketa contributed to this story.