More and more, prime Manhattan office buildings are turning on the “No Vacancy” light.

While the city’s vacancy rate is still much higher than pre-pandemic levels, the best big blocks in better buildings are being snatched up — some reaching 100% occupancy — so brokers are urging tenants to act fast or be left scrambling.

According to Savills, leasing reached a robust 10.5 million square feet in the third quarter — a 20% bump over the previous quarter — bringing the year-to-date total to 32 million square feet, which puts it within reach of 2019’s total leasing of 41.5 million square feet.

The Apple of your eye is going, going, gone unless you act fast. Christopher Sadowski

So far, Colliers has reported 1.85 million square feet leased in the fancy Plaza District, with another 1.05 million square feet at the newer towers at Hudson Yards/Manhattan West.

About 77% of all leases have been relocations, and contrary to what work-from-home proponents predicted coming out of COVID, tenants are expanding by 15%.

“That’s why we are seeing positive absorption in nine of the last 12 months,” explained David Falk of Newmark, who is tracking 27 million square feet of active tenant requirements — 17% more than in 2019.

“There is not enough space to satisfy these needs,” added Bill Elder of RXR, a large office owner.

Although trophy space can cost as much as $300 per foot, CBRE found that average asking rents for all types of offices remain flat at $77.45 per foot, while subleases shrank to 3.1% of available space at a lower asking rent of $57.55 per foot.

“There is not enough space to satisfy needs.”

Bill Elder of RXR

Jason Muss of Muss Development said that conversions to residential and the lease-up of prime space are really changing the narrative: “There is space available, but it is not a situation where there are 10 spaces for every one tenant,” Muss said.

Leasing demand is also spilling over from trophy buildings to the broader Class A office market, said Gaby Rosen of RFR Holding.

Just look at Park Avenue, where vacancy is so low and rents are so high that deals are now bleeding into both Sixth and Third avenues.

Waterman Interests and HPS are tackling 850 Third Ave.’s 605,000 square feet of space. Lois Weiss

“It’s the next logical step for businesses,” said Tod Waterman of Waterman Interests. He teamed up with HPS to tackle a $57 million redevelopment of the 605,000-square-foot 850 Third Ave. — the first project under the city’s M-CORE program. Waterman, who also redeveloped Lever House at 390 Park, is a former competitive golfer. He quipped, “850 is a six-iron away from Park Avenue, and this delta is providing a great opportunity for businesses to move to these redeveloped assets.”

Rents are in the $70s and $80s per foot — half to a third of those on Park Avenue.

Although tenants no longer have leasing leverage on the major avenues or at first-class buildings, they have more negotiating power on the side streets, said attorney Kathy Younkins.

Meanwhile, there’s a lot of pressure on companies to make decisions. “If they aren’t taking advantage of opportunities now, they won’t be available when they are ready to act,” added Adam Henick of Current Real Estate Advisors. “A lot of spaces are leased or spoken for before coming to market.”

The Warehouse at 520 W. 20th St. in Chelsea is now leased to the hilt thanks to growing tech tenants who love the architectural penthouse.

The Warehouse at 520 W. 20th St. in Chelsea had languished since COVID but is now 100% occupied thanks to two tech tenants: Suno.ai and website host Wix. Each absorbed two floors at Elijah Equities’ redeveloped industrial building at asking rents in the mid-$150s per foot. Its new glass penthouse with outdoor terraces was designed by Morris Adjmi.

Adjmi also designed the 58,000-square-foot, formerly vacant Samsung building at 837 Washington St., which had been for sale. Now, rent payment processor Bilt has leased it entirely, with New York State kicking in $6.5 million in renovation tax credits.

AI tenants are also picking up space in buildings that were previously darlings of the tech bunch. “Their growth is so exponential that they are signing deals but could need double, triple [or even] quadruple the space in the next few years,” said Henick. “It creates space-planning challenges, so we work closely with tenants to solve them.”

At Gary Barnett’s 570 5th Ave., IKEA is investing in 70,000 square feet of space in the base. INGKA

Not yet in the stats is a possible 700,000-square-foot deal with the law firm Simpson Thacher & Bartlett at Gary Barnett’s upcoming tower at 570 Fifth Ave. Designed by KPF, it obtained a $292 million investment from IKEA along with a 70,000-square-foot store.

Simpson’s current digs at 425 Lexington Ave. were purchased by Vanbarton Group in 2018. Vanbarton is a leader in redeveloping office buildings into apartments but has not commented on any future plans for the property, which already enjoyed millions in updates. Simpson’s 20-year lease has a rent bump in 2028 and ends in 2033.

But brokers say even if the law firm exits the property, its desirable location by Grand Central Terminal will ensure it fills quickly.

“When any tenant leaves a prime building for new construction, those floors will be backfilled by other tenants looking to grow,” said Jonathan Mazur of Newmark.