Over the last two months, the team has toured each of the Chesapeake hotels and conducted extensive property reviews withon-site senior leadership. We continue to have strong conviction in our underwriting and see upside in both revenue generation and additional expense savings. We are reaffirming our initial expectation of an incremental $24 million of EBITDA in 2020 and a total of $34 million of EBITDA upside in 2021, inclusive of our annual G&A savings of $17 million.
Additionally, given Chesapeake’s outsized exposure to markets such as San Francisco, Chicago and Southern California, which are poised to benefit from strong citywide business and/or renovation tailwinds in 2020, bolting on the Chesapeake portfolio should add an incremental 80 basis points of top line growth to Park’s legacy portfolio next year.
Chesapeake also has made meaningful progress on the anticipated sales of its two New York City assets. As noted in Chesapeake’s recent press release, both hotels are under contract to a single buyer for total proceeds of $138 million, or a 6% cap rate, with an expected close prior to our acquisition of Chesapeake. The sale of these two assets by Chesapeake will further delever the balance sheet of the combined company going forward.
Overall, we have strong conviction about the opportunity, and we remain confident in the long-term benefits of this acquisition. While the transaction offers additional levers to generate incremental shareholder value, it does not divert our attention away from the significant embedded value within Park’s core portfolio. We remain laser focused on aggressively asset managing the portfolio and expect to continue narrowing the margin gap with our peers.
Turning to operations, in the second quarter, comparable RevPAR for the portfolio increased 0.8% against a very difficult year-over-year comparisons and a challenging demand environment.
As expected, group revenues declined by 1.7% during the quarter, a direct result of lapping the strong 18% growth rate in group revenue we produced last year. Softer citywide calendars across several of our key markets were partially offset by healthy production in markets like San Francisco and Orlando, with group pace up nearly 13% and 4%, respectively. Looking forward, we expect group to remain strong for the second half of the year, with overall pace forecasted to increase over 15%.
On the transient side, revenues increased 1.1%, driven by a 4.6% increase in leisure demand, but offset by a 2.5% decline in business transient demand. Despite a relatively healthy economic backdrop, beginning in May, business transient occupancies started to decline, which we believe reflects some corporate uncertainty in light of theon-going trade war with China. That said, we have not witnessed a material change in fundamentals, with group and leisure trends still healthy, and supply in check across most of our key markets. Furthermore, we continue to outperform our comp set as we grew market share during the second quarter at more than 65% of our hotels by an average of 350 basis points, equating to nearly $15 million of market share growth for the portfolio.
In terms of margins, comparable Hotel Adjusted EBITDA margin contracted by only 90 basis points in the quarter to 31.3%. Our asset management initiatives are clearly evident in these results as we kept comparable expense growth to just 2.5%, a notable accomplishment in today’s low RevPAR, high labor cost environment.
Looking at our core markets, our second quarter results were primarily driven by strength in Key West, San Francisco, Hawaii and Santa Barbara, which was partially offset by softness in Seattle, New Orleans, Chicago and New York. Key West was our top performing Top Ten market this quarter, posting a 5.4% RevPAR growth in a clear signal that demand has not only recovered since Hurricane Irma, but surpassed 2017pre-storm demand levels. In San Francisco, despite facing a very difficult year-over-year comp, our two hotels continue to exhibit considerable strength, recording a combined RevPAR increase of 4.5%, outperforming the broader San Francisco market by 320 basis points. Group revenues were up 13%, which is particularly impressive considering group revenues increased 55% in the second quarter of 2018.