Riley's nearly 1,400-square-foot house in a gated community was priced at $35,000 a month in May and was most recently listed at $18,500.
Brosnan's 13,000-square-foot beach estate hit the market at $250,000 a month in June, but was withdrawn from the MLS before a lease was reported.
The micro-market, with its sliver of coastal playground off L.A.'s Westside, mainly attracts tenants from within a 20-mile radius of Malibu and includes people in the entertainment industry, lawyers and business magnates, agents say. A few come from the East Coast and the United Kingdom .
"This is no Saint-Tropez," said Shapiro, referring to the tony Mediterranean resort town in France. "This town closes at 9:30 p.m. in the summer. You get people who want that lifestyle, and that's not the Europeans."
Some are share-the-wealth renters who throw large parties and invite everyone they know to enjoy fireworks shows. Others crave privacy and want to cocoon in lavishly appointed seaside mansions shutting out the world.
Those who fall for Malibu may buy rather than continue to rent. Residential sales there since the beginning of the year have jumped 63% compared with sales for the same period five years ago, according to real estate research firm DataQuick. Sales increased 15% from the same time frame last year.
Statistics only tell part of the rental story, however. Several Malibu houses are leased out summer after summer to repeat customers and never appear on the Multiple Listing Service. Others remain on the market after summer renters have been secured in search of longer-term tenants.
And more potential landlords may be turning to online vacation rental sites, realty agents say, to increase the odds of finding a tenant.
Paid rental listings worldwide at HomeAway have risen about 48% from 2009 to the end of last year, said Vice President Jon Gray, who oversees the business operations for HomeAway and two other U.S. vacation rental sites. Internet listings provide another avenue for homeowners trying to get the most out of their investment.
"People list a second home looking to rent it for a pretty long period of time overall — 20 or 30 weeks," Gray said. "Our average property rents out 19 weeks a year and generates $28,000 in rental income for the owner."
Such online sites handle mega-buck rentals, too. Brandon Ezra, who started the vacation rentals site JetLiving.com in Malibu, once had a local property lease at $100,000 a month.
It makes financial sense, he said, for those who may use their second homes only a couple of weeks a year to lease out their places. As homeowners in Malibu and other coastal locales know, rust is a constant foe.
"It's not cheap," Ezra said, "to maintain these houses."