Howard Schwimmer
Analyst · Citi
Thank you, Michael, and thank you, everyone, for joining us today. Market fundamentals in infill Southern California continued with unprecedented strength in the first quarter despite impacts associated with the pandemic. Vacancy tightened and demand accelerated as a diverse group of growing industries and e-commerce companies absorbed warehouse space at a torrid pace.
Over the past 12 months, according to CBRE, our infill markets experienced strong rental rate growth with asking rents up 4.9% on a weighted average basis. For further perspective, based on our internal portfolio analytics, we believe market rents increased by an estimated 9.3% over the prior year for comparable product within our target infill Southern California markets.
Our target markets, which exclude the Inland Empire East, ended the first quarter at 1.9% vacancy. By comparison, our same-property portfolio ended the first quarter with 98.6% occupancy, outperforming the market by 50 basis points, a testament to the high-quality of the Rexford portfolio, our strong tenant retention and elevated new leasing volume.
Of our top 20 largest expiring leases this year, approximately 80% of spaces, representing 1.4 million square feet have already renewed, been retenanted or are in lease negotiations. The remaining 675,000 square feet of top 20 spaces are headed for value-add repositioning and future lease-up.
A recent leasing example in our San Gabriel Valley portfolio demonstrates the strength of our market. During the quarter, our tenant occupying about 150,000 square feet was dismayed with a higher renewal rate and spent months of searching for alternative, less expensive space. Unable to find any similar functional space, the tenant finally renewed with us, but at a rent that was a full 21% higher than our original proposal had they not waited.
In the end, we generated a cash re-leasing spread of 95%. This is representative of the unprecedented pace of rent growth within our infill markets and set another record for all-time high rent for the submarket. In addition, we obtained 3.25% contractual annual rent increases through the term of the lease, which exceeds the 3% historical standard for our markets.
As a general note, we are increasingly pushing our annual rent bumps above 3% and in some cases, as high as 4%. Year-to-date, we completed 11 acquisitions, which included 807,000 square feet of buildings including 26.9 acres of low coverage outdoor storage sites and land for future redevelopment for an aggregate purchase price of $191 million. 82% of these transactions were off-market or lightly marketed, enabled through our proprietary research-driven sourcing methods. These investments are projected to generate an aggregate 5.2% or greater stabilized yield on total investment and provide strong value-add cash flow growth over time, initially contributing about $0.02 of FFO per share through the remainder of 2021 and growing to about $0.09 per share after repositioning or redevelopment.
We currently have over $450 million of acquisitions under LOI or contract. These acquisitions are subject to customary due diligence with no guarantee of closing. We will keep you apprised as transactions are consummated.
On the disposition front, we sold 2 properties totaling $21 million in the San Fernando Valley and Inland Empire East submarkets. The proceeds were used to tax efficiently fund, a portion of our acquisition activity. Moving forward, we expect to continue to sell assets opportunistically to unlock value and recycle capital.
Turning to repositioning and redevelopment activities. We have over 3 million square feet of current and planned value-add projects throughout our portfolio. Of these, 1.3 million square feet of current projects in repositioning, redevelopment or lease-up, which are detailed in our supplemental, are estimated to deliver an aggregate return on total investment of 6%. These projects are expected to deliver a substantial value creation as our stabilized yield represents more than a 200 basis point premium compared to the sub-4% market cap rates that they would be valued at in today's market.
And with that, I'm pleased to now turn the call over to Laura.