Put differently, there is no increase of trading volumes without underlying motives, and when such an increase of activity occurs in a bullish set-up there is certainly a good reason for the asset to move up:

June 26th Amerant Bancorp (NASDAQ: AMTB, AMTBB) announced:

Amerant Bancorp to Be Added to the Russell 2000® Index | Mercantil Bank Holding Corp. CORAL GABLES, Fla., June 26, 2019 (GLOBE NEWSWIRE) — Amerant Bancorp Inc. (NASDAQ: AMTB and AMTBB) (“the €œCompany”€), announced it will be included in the annual reconstitution of the small cap Russell 2000 Index, effective at the close of the stock market on Friday, June 28, 2019.
Source: investor.amerantbank.com/news-releases/news-release-details/amerant-bancorp-be-added-russell-2000r-index

When a stock integrates an index the managers of index tracking funds or ETFs are forced into buying this stock to add it to their investment product, which justifies the increasing volumes but also denotes insider interventions as it happened before the news release.

We sent an AMTB buy signal on June 16th with increasing volumes as one of our selection criteria and suggested an initial stop set at $17. After triggering our breakout level at $20 the stock retreated but now appears to have found some buying support in the $17.5 area.

AMTB Weekly Price Chart

This said, the news may not prevent AMTB to decline, but the odds are certainly in favor of a continuation of the uptrend.