Eight of California’s top owners of apartment buildings and their related business entities have donated nearly half of the $74 million raised to defeat Proposition 10, according to a Los Angeles Times analysis of state campaign finance data.

Many of the landlords are publicly traded real estate investment companies with portfolios that span across the country. In earnings calls and investor conferences over the last year, company executives have spent significant time reassuring Wall Street they’re doing everything they can to defeat Proposition 10.

Their goal, the executives and market analysts say, is not just winning in California, but also preventing a wave of rent control measures that might follow nationwide. At this fall’s meeting of the National Multifamily Housing Council in Washington, D.C., organizers held a session on combating Proposition 10, which they called an “existential threat to the industry.”

“We’ll fight very hard at this level, and we will continue in every other place that talks about having rent control — we’ll fight at that level as well,” said David Neithercut, president and chief executive of Chicago-based Equity Residential, the country’s third-largest apartment owner, at an investor conference in September.

Proposition 10 would repeal the Costa-Hawkins Rental Housing Act, a state law that prohibits cities and counties from imposing most new forms of rent control including on single-family homes or apartments built after 1995. If the initiative passes, local governments would be free to put any restrictions on rents that they choose.

Total fundraising for the ballot measure has topped $100 million, making it one of the most expensive campaigns in state history. Opponents have outraised supporters 3 to 1.

Historically, support for California ballot measures has declined as deep-pocketed opponents use their financial advantage to sow doubt about what an initiative might do. The Proposition 10 campaign is playing out the same way.